Promissory oaths

249. Definition. 1. A promissory oath is an act by which someone, under invocation of the divine name, obligates himself to doing or omitting something.

a. Therefore two things are confirmed in a promissory oath: alpha. the truth of the present assertion, that is, that the one swearing actually has the will of doing the work promised; and beta. the truth of the future execution, that is, that he will actually do the work promised; and for each truth he invokes God, and indeed as witness of the former and as surety of the latter. Insofar as a promissory oath regards the present will of doing the work promised, it is assertory; but insofar as it regards future fulfillment, it is exclusively promissory, and under this respect it is considered here.

b. In a promissory oath God is not introduced as witness of future execution: for testimony is borne only concerning past or present truth. For confirming a promise as to future execution, a surety is customarily introduced; but God cannot properly be called a surety: for He Himself does not assume the burden of fulfilling in the default of the one promising. Therefore suretyship with respect to God only signifies that God, by His authority, gives greater firmness to the promise made before Him, insofar as the one promising through the oath takes upon himself the obligation of fulfilling from reverence toward God, and therefore from the virtue of religion, what he promises.¹

2. A twofold promissory oath is distinguished, simple and confirmatory, according as the thing to which someone obligates himself to do or omit is a mere resolution or a promise made to another.

If the first obtains, there is had a sworn resolution: I swear that I shall fast; if the other obtains, the promissory oath either confirms a promise made to God, and is a sworn vow: I swear that I shall observe the fast promised to God; or it confirms a promise made to a man and accepted by him, and is a sworn pact: I swear that I shall fulfill the betrothal contracted; or finally it confirms each, namely the promise made to God and to man, and is a vow sworn with a pact.

¹ Cf. Suarez, l. 3, c. 16, n. 10 ff.

250. Principles. 1. A promissory oath induces an obligation of religion of keeping the things promised: for the one swearing is held, from reverence toward God, whom by swearing he invoked as surety, to keep the promise.

a. Therefore he who violates a simple promissory oath commits one sin against religion; he who violates a sworn vow sins in two ways against religion, namely against fidelity through violation of the vow and against reverence owed to God through violation of the oath; he who violates a sworn pact commits two sins, one against fidelity or justice, the other against religion.

b. The obligation of the oath, which accedes to and is superadded to a promise made to a man and obligating from justice, is altogether personal; accordingly, it affects only the one swearing and does not pass to his heirs.

c. Theologians ask whether the obligation of a vow or of an oath is greater. The question must be understood in such a way that the comparison is made between vow and oath insofar as it is promissory, not insofar as it is assertory. Now to the question so proposed it seems it must be answered that the obligation of a vow is greater than that of an oath. For a vow obligates from fidelity toward God; but a promissory oath, insofar as it is an oath, properly obligates not from fidelity but from reverence owed to God: for by an oath nothing is promised to God, but He Himself is invoked that by His authority He may give special firmness to the resolution or promise made to another. Wherefore transgression of a promissory oath is not a sin of infidelity, but a sin against reverence owed to God.¹

2. A promissory oath, whether the promise was made to God or to man, obligates under grave or under light obligation according as the thing promised is grave or light: for since the obligation of an oath is less than the obligation of a vow, and a vow in light matter obligates only under light obligation, an oath also in light matter obligates only under light obligation.

Therefore an oath not fulfilled is a grave or light sin according to the nature of the matter. Therefore he who does not fulfill a light thing which he promised by oath, or a small part of a grave thing, sins venially. There are indeed some who say that a promissory oath always obligates under grave obligation, because in a promissory oath God is adduced as witness of future execution; but in this oath God is adduced only as witness of the contracted obligation, so that this cannot be violated from the intention of the one swearing without irreverence inflicted upon God. But this irreverence is grave or light according to the nature of the matter.

3. A promissory oath concerning an impossible, illicit, or useless thing induces no obligation. The reason of the first is that no obligation is given to the impossible; the reason of the second is that likewise no obligation is given to an evil thing; the reason of the third is that a vain or indifferent thing does not yield to the worship of God; therefore we cannot obligate ourselves to it for worshiping God.

a. If the thing afterward ceases to be illicit or useless, the oath does not revive: for: that which by law does not subsist from the beginning is not strengthened by the passage of time.²

b. If the oath is concerning a thing indeed honorable, but less good, it must be distinguished whether the promise was made to God alone, or whether it was made for the benefit of a third party. If the first, the oath does not obligate, because it does not yield to the worship of God that a work indeed good, but impeding a greater good, be done; if the other, it obligates, provided the promise has also been accepted by the other, because the acquired right of the third party must be preserved. Therefore a cleric who swore that he would serve some church is held by the oath, unless he obtains dispensation, even if this impedes entrance into religion.

Whether a promissory oath unjustly extorted obligates. Just as a vow unjustly extorted is not valid, so also an oath unjustly extorted must be said not to be valid: for a promise which is founded upon injury is invalid by the law of nature; moreover, God is not judged to confirm by His authority a promise of this kind unjustly extorted.

¹ Suarez, l. 2, c. 3, n. 7.

² Non firmatur, reg. iuris 18, in 6.

251. On the interpretation of a promissory oath. In the forum of conscience a promissory oath must be interpreted according to the mind of the one swearing: for the obligation which he imposes upon himself by oath depends upon his intention. But if the intention of the one swearing is not established, it must be interpreted according to the following rules:

1. An oath must be interpreted strictly: for odious things are to be restricted; but that an oath is odious is gathered from the grave obligation which it induces and from the danger of violation. Moreover, the one swearing is judged to have willed to obligate himself as little as he could.

2. A promissory oath follows the nature and conditions of the act (resolution, promise, contract) to which it is added: for an oath does not change the nature of the act, but supposes the act and superadds to it an obligation of religion. And indeed, since the act is the principal, but the oath is the accessory, the principle holds: the accessory follows the nature of the principal.¹

a. Therefore alpha. an oath added to an act invalid by the law of nature, for example to a promise extorted by (substantial) deceit, is itself invalid. beta. Since every promise contains this tacit condition, unless it be remitted, the oath also contains the same condition, and accordingly ceases when the promise ceases. gamma. Sworn betrothals can be dissolved by mutual consent just as non-sworn betrothals can.

b. He who swore that he would observe the statutes of some congregation, college, office, etc., is not held to observe these except in that way by which they obligate of themselves. Therefore alpha. he is not held to observe those which have already gone into desuetude and are not observed by the greater part of the community; beta. those which of themselves obligate only under light obligation, or under penalty only, or from mere fittingness, are not to be observed otherwise because of the oath; gamma. by transgressing those which obligate under grave or light sin, he commits besides a grave or light sin against religion.²

c. An oath of keeping a secret does not obligate when the obligation of the secret itself ceases; but violation of a secret obligating in conscience will be a grave or light sin against religion according as the secret itself obligates under grave or light obligation, because the obligation of the oath follows the obligation of the secret.³

d. Oaths of parents to punish children for the most part are not true oaths, because there is not present the intention of swearing, but only of frightening the children. But if they are true oaths (sworn resolutions), they must be put into execution unless their obligation ceases; but this ceases if execution of the resolution becomes irrational, as if the penalty would not correct the child but would only embitter him: for the oath is accessory to the resolution, and when this ceases, the oath also ceases.

3. A promissory oath must be interpreted according to the conditions which are understood in every promise; conditions of this kind are: a. if I shall be able, both physically and morally; b. with the right of the superior preserved, who from a just cause can irritate or dispense in the obligation; c. if the thing shall not have been notably changed: for if it has been notably changed, the intention of the one promising did not refer to it; d. if the other shall have kept faith; e. unless the other yields his right.

According to these rules the oath of not playing is to be interpreted.

a. If the oath is made from zeal for mortification and religious perfection, the one swearing is held to abstain from every game.

b. If the oath of not playing in general is made without the intention of greater perfection, the one swearing is not held to abstain from honorable and licit play: for the end of this oath is judged to be lest time be spent uselessly and money squandered.

c. He does not act against an oath of not playing who assists others playing, observes them, gives money to someone which is to be exposed in play, and helps him by his advice: for he who does these things is not said to play.

¹ Accessorium, reg. iur. 42, in 6.

² St. Alphonsus, n. 181.

³ St. Alphonsus, n. 183.

252. On the oath of fidelity. By this name is signified the oath of obedience and fidelity which political authority is accustomed to exact from its subjects, not indeed from all, but from magistrates, soldiers, and primary officials of the kingdom.

a. This oath (supposing a legitimate government) of itself is honorable and licit, unless it is exacted from ecclesiastics, and unless it contains anything which is against the rights of God and the Church: for since subjects are held to obey valid laws of the political power, this oath can be exacted and furnished by subjects.

b. It is clear that an oath of furnishing obedience to laws which are contrary to the rights of God and of the Church is illicit; nevertheless, from a sufficient cause it is lawful to furnish an oath of obedience, even if some laws are contrary to divine laws, under this twofold condition: alpha. that the clause be added: with the laws of God and of the Church preserved; beta. that, for preventing scandal, if there is need, it be declared that the Holy See has permitted the oath with this clause added.¹

It is not necessary that the clause be expressed, or that mention be made of the liceity of the oath, if it is publicly known, for example from the declaration of the prince, that the oath is to be accepted in this sense,² or if, the circumstances being considered, scandal is not to be feared, because, for example, from the quality of the person it is already understood that the oath is not made in another sense.

c. It is not lawful to exact this oath from ecclesiastics, nor can they themselves licitly furnish it, because the oath is repugnant to the personal immunity which they enjoy. Nevertheless, alpha. if custom makes the oath honorable, it can licitly be exacted and furnished. For this reason those who receive an office from the government are accustomed to make the oath of fidelity. beta. It is licitly furnished if a pontifical privilege permits it. For this reason bishops are accustomed to swear before the prince before they undertake governing their church.

d. Those who make this oath obligate themselves only to this, that they will to be subject to the laws and to plot nothing against legitimate authority; and if they are public officials, that they will discharge their office according to the laws, but not that they will to observe individual precepts of law also from religion.

¹ S. Poenitent., 10 Dec. 1860. Cf. Scavini, Theologia moralis^2 (Mediolani: Olivia, 1890), t. IV, p. 431 ff.

² It is established that this was done in Austria. Cf. Archiv f. kath. KR., XXVI, p. 250 ff.

253. On the cessation of a promissory oath. A promissory oath ceases: a. by cessation of the end; b. by condonation made by him in whose favor the oath was made; c. by irritation; d. by dispensation; e. by commutation. Therefore the obligation of an oath ceases in the same ways in which the obligation of a vow ceases, with one exception, condonation, by which an oath can cease, but not a vow.

1. On condonation. a. Just as oaths which are made in favor of another do not induce obligation unless they are accepted by the other, so afterward they can be relaxed by the same, if he renounces the favor furnished to himself.¹

b. Just as ecclesiastical authority, so also civil authority can relax the obligation of an oath made concerning those things which are subject to civil power. For by the very fact that civil authority remits an obligation arising from a right acquired for itself, the obligation arising from the oath is also indirectly extinguished: for the accessory follows the principal.

2. On dispensation. Not only he who has ordinary power, but also he who has merely delegated power of dispensing in vows can dispense also in oaths, whether they are annexed to a vow or are not, unless at the same time there is question of the acquired right of a third party, from which that person is unwilling to yield: for vows and oaths are equated as to dispensation.

a. Although all concede this concerning him who has ordinary power, such as a bishop, nevertheless there are some who with St. Alphonsus (n. 190) deny that he who has only delegated power of dispensing in vows can dispense in oaths. But since St. Alphonsus himself concedes the probability of the affirmative opinion, it is safe in practice, because in the case of speculatively probable power the Church supplies. Indeed, many probably teach that he who has delegated power of dispensing in vows can also dispense in sworn vows, in which the double bond of vow and oath concurs.²

b. He who can dispense in vows can also dispense in oaths which turn upon the matter of reserved vows, unless a vow accedes, because oaths are not reserved. But if a reserved vow has been confirmed by oath, he cannot dispense unless he can dispense in reserved vows.

c. Regular confessors from special privilege (of Gregory XIII and Paul III) can dispense in oaths and commute them, unless they were made in favor of a third party and accepted by him.

¹ Suarez, l. 2, c. 39, n. 1 ff.

² Cf. Suarez, De voto, l. 6, c. 14, n. 6; Genicot, Instit. theol. mor., I, n. 307; Ballerini-Palmieri, II, n. 595 ff.

The effect of a promissory oath is to bind the person swearing to do what he promises by an additional obligation derived from the virtue of religion, which requires that out of reverence for God we should religiously perform what we promised under oath. If we fail to do this in a matter of moment, grave sin will be committed, as all acknowledge. Moreover, as is obvious, if when the oath is taken there is no intention of keeping it, a grave sin of perjury is committed, for perjury is never venial on account of triviality of matter. If, however, when the oath was taken there was a serious intention of keeping it, but afterwards there was a failure to do so in a matter of small moment, a probable opinion holds that such a want of fidelity in a small matter cannot be more than a venial sin.

The obligation imposed by a promissory oath is of strict interpretation, and follows the nature of the act or contract to which it is annexed, so that it is dependent on all the conditions and limitations with which law, or custom, or the circumstances invest the act or contract. For a promissory oath is accessory and follows the nature of the principal act to which it is annexed. And so an oath to observe the rules or statutes of a corporation is understood to refer only to those that are in force.¹

¹ Can. 1318, 1321.

An oath should conduce to the service and honour of God; it cannot be a bond of iniquity; and so an oath to do what is wrong is sinful and of no effect. Similarly, an oath to do what is useless, or which hinders greater good, is null and void. In case, however, another party has acquired rights under an oath, justice requires that this should be kept, and so the mission oath, by which a sworn promise is given to serve a particular church or mission, binds a missionary priest even though he is persuaded that he has a vocation to the religious state.

In accordance with rules of canon law, an oath extorted by violence or grave fear is valid, but it can be dispensed by an ecclesiastical superior. Moreover, an oath taken without violence or fraud by which one renounces a private advantage or favour granted him by law must be kept as long as it can be kept without sin (Can. 1317, sec. 2, 3).

I. Notion. A promissory oath, as we have said (n. 682), is the invocation of God to give assurance concerning one's own future action. In an oath of this kind, as likewise we have already noted, God is invoked: 1. as witness of the present will to place the action; 2. quite probably as patron of the future execution, that is, God is invoked so that He may give authority and force to the proposal or promise; "which," Suarez says, "I explain by a human example. For men are often accustomed to promise, or to make a compromise, or to enter betrothals, before a king or another man of great authority, not so that he should properly be a surety undergoing an obligation, nor even so that he should be witness of the future execution, but so that he may furnish authority to the contract, and so that the contracting parties may understand that they will do injury to him if they do not fulfill the promises."¹ These things also are held by St. Alphonsus as sufficiently founded (III, 173).

Others judge that God in a promissory oath is invoked as witness of future truth, and they appeal to the natural meaning of the words by which the said oath is expressed. Suarez tries to weaken this opinion with these words: "With respect to a future fact He cannot be brought in as witness, for testimony is not given concerning a thing not yet done. And although future things are present to God, nevertheless, insofar as divine testimony is invoked through an oath, there is not asked from God, so to speak, testimony concerning a future thing as it is present to Him, but as it is in the word of the one promising. But in this way testimony does not fall upon that word except insofar as it is capable of truth when it is spoken; therefore, with respect to a future fact, as to be confirmed by that word, God is not invoked as witness, but as surety, to whose honor and authority it pertains that he who has sworn should effectively accomplish what he has asserted or promised."²

According to others, God is invoked as surety (properly so called), that is, in such a way that He, as it were, promises or proposes together with the one swearing. But that is not proved, so that God, as regards practice or obligation, can be held as only patron of the future execution (n. 689). Nor is a surety properly so called understood by Suarez, as is clear from the words cited.

As to the opinion of St. Thomas, II-II, q. 89, aa. 1, 7, and 9 should be compared.

¹ De iuramento, bk. 3, c. 16, n. 10.

² Cited place.

II. Division. A promissory oath is divided into a simple promissory oath, or one standing by itself, and a confirmatory promissory oath. A simple oath is one which is emitted without a promise (or any obligation), whether previously existing or made together with the oath. A confirmatory oath is one emitted in confirmation of a promise (or of any obligation), whether previously existing or made together with the oath, either to God (a sworn vow), or to man (a sworn promise), or to God and man (a vow sworn together with a promise). Therefore the matter of a simple promissory oath is future action as such; but the matter of a confirmatory oath is the future fulfillment of a promise or of any obligation.

III. Requisites for validity. For validity some things are required on the part of the one swearing, others on the part of the matter.

1. On the part of the one swearing, almost the same things are required as on the part of the one vowing for the validity of a vow (n. 642). It suffices to add these things:

a) For the validity of a confirmatory oath there is required either a pre-existing obligation, or the intention of actually promising something either to God (a vow) or to man. For the validity of an oath standing by itself these things are not required.

It is disputed whether or not for a promissory oath there is necessarily required an intention of obliging oneself by force of the oath. But it seems this must be denied, because for the substance of a promissory oath there is required only the intention of invoking God to give assurance concerning one's own future action (n. 682), not however the intention of obliging oneself by force of that invocation, although that obligation follows as a necessary effect.

b) Fear does not obstruct validity according to these words of can. 1317, § 2: "An oath extorted by force or grave fear is valid, but can be relaxed by an ecclesiastical superior" (St. Thomas, II-II, q. 89, a. 7, ad 3; St. Alphonsus, III, 174).

2. On the part of the matter it is required that it be honorable, not illicit or idle. The reason is that divine authority cannot be the bond of an inequitable or vain thing (St. Thomas, II-II, q. 89, a. 3, and a. 9, ad 3; St. Alphonsus, III, 176).

Corollary I. Oaths of parents to punish their children are commonly invalid or at least do not oblige, either because they were about a useless matter, or rather about disordered vengeance, or because the delinquents have already been corrected or have promised amendment (St. Alphonsus, III, 186). Likewise oaths of merchants not to sell for less or not to buy for more, even if they are made seriously, commonly do not have force, because ordinarily they are about a useless matter.

Corollary II. An oath of fidelity to a political Constitution which contains some things contrary to divine or ecclesiastical law is valid insofar as it is restricted to licit things. It is licit if that restriction is expressly added (namely by adding these or similar words: "saving divine and ecclesiastical laws"), or, as happens today, is drawn from usage.¹ Likewise valid and licit is an oath of fidelity to a usurping Prince, when he peacefully possesses the kingdom (St. Alphonsus, I, 94; II, 74).

Corollary III. An oath emitted by a cleric to remain in the diocese and not to enter Religion is valid, because it regards a thing owed by force of the promise made together with the oath, and confirmed by the oath itself.

Corollary IV. An oath concerning matter partly impossible or inept has force and obliges as to the other part, if the matter is divisible by its nature and also intended divisively. Hence, for example, a prodigal sworn promise (or not sworn) can have force in part.

¹ Cf. Brief of Pius VI Charitas, April 13, 1791; Sacred Penitentiary, December 1, 1866 (Acta Sanctae Sedis 1866, p. 675).

IV. Effects. 1. An oath added to an invalid act (for example, to a contract, promise, or vow) does not render it valid; nor, added to a rescindable act, does it render it unrescindable; since an oath does not change the nature of the contract, promise, or vow, as that exists of itself or by law. To this refer these words of can. 1318, § 2: "But if an oath is added to an act directly tending to the harm of others, or to the prejudice of the public good or of eternal salvation, the act obtains no firmness from this."

2. An oath added to an invalid act does not induce an obligation, because an oath added to an act follows the nature and conditions of the act to which it is added (can. 1318, § 1), or because the accessory follows the principal (St. Alphonsus, III, 180).¹

3. An oath added to a valid act, and likewise an oath standing by itself, induce an obligation, as is clear both from Sacred Scripture,² and from what is soon to be said about the quality of the obligation. Nevertheless, an oath added to a valid act begins and ceases to oblige with the act to which it is added; for, as was said, it follows the nature and conditions of this act. But more must be said about the obligation of a promissory oath. Moreover:

a) A promissory oath induces an obligation of religion (can. 1317, § 1). The reason is that the reverence owed to God demands that the action be placed in the case in which God has been invoked as patron of the execution, as happens in a promissory oath. But the obligation of an oath differs in species from the obligation of a vow, because the former regards God as witness of the present will and patron of the future execution; the latter regards Him as creditor.

Corollary. He who violates a promissory oath perpetrates at least two sins: namely, against the obligation of religion induced by the oath, and against the obligation, whether of religion induced by a vow, or of another virtue, induced by a promise made to man. A third is added, if he violates an oath added to a vow with a promise made to man.

b) A promissory oath induces a grave obligation of religion, if it regards a grave matter; for it is grave irreverence to omit a grave act as to which God has been invoked as patron. If it regards a light matter, it is disputed whether the obligation is grave or light. But it is quite probably only light, because grave irreverence does not appear in the fact that an action of lesser moment is omitted, even if God has been invoked as its patron (St. Alphonsus, III).³

Nevertheless note that he sins gravely who, while he swears, does not have the will of standing by the promises; because in a promissory oath God is invoked as witness of the present will. But it is grave irreverence to invoke God as witness of what is false.

c) As to establishing the extension of the obligation, the following rules have force:

a) An oath must be interpreted strictly according to law and according to the intention of the one swearing, or, if he acts with deceit, according to the intention of him to whom it is sworn (can. 1321).

b) A confirmatory oath follows the nature and conditions of the act to which it is added (can. 1318, § 1). Therefore its obligation extends itself to the same things to which the act - for example, a vow or promise - in confirmation of which it is added, extends.

Corollary. An oath which regards matter of law obliges according to the limits of law. Hence, for example, a pastor who has sworn residence can be non-resident insofar as this is conceded by law. An oath of observing statutes or rules does not oblige as to rules abrogated by legitimate desuetude; furthermore, an oath of this kind obliges under grave obligation or under light obligation or to penalty alone, according as the statutes themselves of themselves oblige under grave obligation, or under light obligation, or to penalty alone (St. Alphonsus, III, 181).

¹ Nevertheless, it is not repugnant that an oath added to an invalid act induce an obligation; for strictly speaking someone can oblige himself independently of the value of the act to which the oath is added. But these things are almost hypothetical.

² Matt. 5:33.

³ Those who teach that God in a promissory oath is invoked either as witness or as surety of the future action rightly conclude that the obligation of the aforesaid oath is always grave: for it is grave irreverence to constitute God a false witness or an unfaithful or changeable surety. But the antecedent is not proved.

V. Cessation. From can. 1319, a promissory oath, or the obligation induced by an oath of this kind, ceases:

1. If it is remitted by him for whose advantage the oath had been emitted (St. Thomas, II-II, q. 89, a. 9, ad 2; St. Alphonsus, III, 193). And that remission quite probably is made validly and licitly even when the oath was emitted principally in honor of God. "The reason is that, although the promise was made to God, it was nevertheless always made dependently on the will of the man to whom it was sworn, namely: if he does not remit the execution" (St. Alphonsus, cited place).

2. If the thing sworn is changed substantially; or, when the circumstances have changed, becomes either evil or altogether indifferent; or finally impedes a greater good. The former is drawn from the fact that the intention of the one swearing is not judged to have extended itself to matter substantially or notably changed, as was said concerning the intention of the one vowing (n. 653). The other things follow from this: that the thing sworn, if it becomes evil, or indifferent, or an impediment to a greater good, ceases to be matter apt for an oath (n. 688). Notice, however, that honorable matter promised and accepted in favor of a third party, even if perhaps less perfect in itself, nevertheless here and now remains more perfect, indeed is commanded, on account of the right acquired by the third party (n. 688).

3. If the final cause or the condition under which perhaps the oath was given is lacking. See what was said about a vow, n. 655.

4. By irritation, dispensation, or commutation, according to the norm of can. 1320. Moreover, from the cited canon:

a) The same persons who can irritate vows can irritate promissory oaths, and for the same reason (n. 662). They can irritate them - equally as vows - even if the irritation tends to the prejudice of others, even though these refuse to remit the obligation.

b) Likewise the same persons who can dispense or commute vows can dispense or commute promissory oaths, and for the same reason (n. 671); but if the dispensation of the oath tends to the prejudice of others, the Apostolic See alone can dispense or commute the oath on account of the necessity or utility of the Church (St. Alphonsus, III, 189, 192).

Obligation Imposed by Promissory Oath.—An assertory oath imposes the obligation of telling the truth and of repairing any damage that results from the falsity or injustice of the declaration. In addition, a promissory oath binds one in virtue of religion to perform one’s promise; for, as said above (2249), an oath must have truth. Hence, Scripture bids those who have sworn to fulfill the promise (Matt., v. 33) not to make the word of no effect (Num, xxxi. 3). But the thing promised must be possible and lawful, or otherwise the oath lacks judgment or justice. (a) Thus, an impossible promise is not binding, for no one can oblige himself to perform what he cannot perform (cfr. 2201); (b) an unlawful promise is not binding, for no one can oblige himself to perform what he is bound not to do. Thus, an oath to revenge murder by murder is null, and sin is committed both in taking and in keeping it.

Obligation Imposed by Negative Oaths.—The obligation of a sworn promise not to do what is better (e.g., not to take a vow), or to do what is vain and useless (e.g., an oath to count the steps one takes), depends on the circumstances. (a) If there are no rights of a third party involved, these oaths do not hold (e.g., he who swears not to vow acts laudably in disregarding the oath). For one may not call God to witness or be guarantee for that which is less pleasing to Him, or which in no way honors Him, and for which there is no claim on the part of a third person. (b) If there are rights of a third party involved, these oaths oblige one to give the third party what he is entitled to from the promise (e.g., a nurse who swears to remain with a sick person may not violate the oath by entering religion).

Obligation of Oath Is Personal.—An oath added to a promise made to man and obligatory in justice is personal, and hence it binds the one who makes the oath, but not his heirs (see 2216).

Interpretation of Promissory Oaths.—(a) An oath should be interpreted strictly, for the presumption is that the promisor intended to place upon himself the least possible burden. Thus, if a person swears to observe the statutes of a certain Congregation, it should be understood that he pledges himself to present, not to future statutes; if he swears not to gamble, the oath does not forbid games in which money is not played for. But if the promisor acts deceitfully, the oath is to be interpreted according to the intention of him who receives the promise (Canon 1321).

(b) An oath is always subject to the limitations and reservations which the nature of the case, law, or custom demands. Hence, even though an oath is made unconditionally, the following conditions are understood: “If fulfillment will be physically and morally possible,” “saving the rights of superiors,” “unless the other party renounces his right,” “unless the other party fails to keep his part of the agreement,” “unless there comes a notable change in conditions.” If the promisor explains beforehand to the promisee what he understands by the oath, he swears only in the sense thus set forth by him.

(c) An oath follows the nature and conditions of the act (e.g., resolution, promise, vow, contract) that it confirms, for the accessory follows the principal. Hence, if the act to which the oath is attached cannot be obligatory (e.g., an act detrimental to eternal salvation, or the public good, or the rights of a third party), the oath gives no strength to this act (Canon 1318); if the act is naturally invalid (e.g., a promise obtained through substantial fraud), the oath is also invalid; if the act does not become effective (e.g., a promise not accepted), neither does the oath become effective; if the act ceases to oblige (e.g., a promise of secrecy made for a time), the oath also ceases to oblige; if the act is not obligatory under grave sin, the oath is not obligatory under grave sin (e.g., if one swears to observe the statutes of a university, one is not bound to observe those that are commonly neglected, one commits no sin by transgressing those that are merely penal or optional, and one commits no grave sin by violating those that oblige under venial sin).

Kind of Obligation Produced by a Valid Promissory Oath.—(a) The obligation is one of religion, because the significance of the oath is that it adds the duty of respect owed to God to the duty of fidelity owed to the promise. Men swear in order to make their promises more trustworthy through the sacredness of the oath. The violation of a promissory oath is, therefore, always a sin against religion. There are other sins added in some species of oath, namely, a second sin against religion in case of a sworn vow, a sin against justice and fidelity in case of a sworn contract, a second sin against religion and a sin against justice and fidelity in case of a sworn vow and contract (see 2246 a).

(b) The obligation, other things being equal, is less than that produced by a vow, because the vow binds in virtue of fidelity to God, but the oath only in virtue of respect. The obligation of fidelity seems to be stronger, because unfaithfulness always contains disrespect, but not vice versa. Moreover, in the case of a vow not only the fulfillment of the promise, but the thing promised itself is sacred, which is not true in the case of an oath. An assertory oath, however, seems to be more binding than a vow, because it is a greater injury to God to make Him the witness for falsehood than to break a promise made to Him.

Degree of the Obligation of a Valid Promissory Oath.—(a) The obligation is grave, from the nature of an oath, because the virtue of religion is preeminent among the moral virtues (see 2146). There is no doubt that mortal sin is committed when one gives a sworn promise and has no intention to fulfill it, for this is perjury (see 2250 b); and also when one unjustly refuses to live up to an important engagement made under oath, for this is irreligion and injustice in a serious matter. The remarks on grave matter in vows (2211) apply here, but, since the vow obliges more strictly, a somewhat greater amount is needed for serious matter in violation of an oath.

(b) The obligation may be light on account of the smallness of the matter involved. Even a vow, which is more binding than an oath, may be of venial obligation in this way (see 2211). A person who makes a promise under oath, fully intending to keep the promise, but who later changes his mind without sufficient reason, does not show disrespect to God, since when the oath was made he intended to abide by it, and does not seriously injure his neighbor, since, as we suppose, the matter of the oath is small. The sin, therefore, is one of inconstancy or levity, and, if there is disrespect, it is slight. Thus, if a person who had sworn to drink no more wine took a drop now and then, these transgressions would be only venial. Some authors, however, believe that every unfaithfulness to a promissory oath, no matter how small the subject-matter, is a grave sin, because perjury is committed by the breach of promise. This is commonly denied, because the meaning of a promissory oath is that God is called on to witness the truth of a present intention and the obligation (great or small) of a future performance.

What is the obligation of a promissory oath? - Every promissory oath concerning a licit and honorable thing, besides the obligation of justice or fidelity which arises from a simple promise, also induces an obligation of religion. The reason is that a promise per se already obliges, and with divine testimony invoked it is confirmed and strengthened. "For someone is bound to make true what he swore; otherwise truth is lacking in the oath." S. Th. 2. 2, q. 89, a. 7. But an oath concerning an illicit or plainly useless thing by no means obliges, because an oath, as an act of religion, cannot be a bond of iniquity or of an idle thing. R. 58, de R. I. in 6. Oaths of this sort do not revive, even if the thing afterwards ceases to be idle or illicit according to R. I. 18 in 6: "That which by law does not subsist from the beginning is not strengthened by lapse of time."

Nor likewise does an oath impeding a greater good oblige, for example, of not entering religion or of marrying, unless someone swore in favor of another. For then, without injury to the other's right, he cannot embrace the evangelical counsels. Thus alumni of the College of the S. C. de P. F. cannot enter religion without permission of the Holy See, because of the oath by which they are bound. Struggl 24 seqq.; L. 172, 176; S. Th. 2. 2, q. 89, aa. 7, 8; Quodl. 5, a. 27; Scavini, ed. 12, Milan, 1874, v. 2, n. 229; v. 4, nn. 243, 244, 245; cf. here 554. Alumni of the Urban College of Propaganda Fide promise by oath the observance of the laws of the College, that they will not enter a religious order without special permission of the Holy See, that they will ascend to sacred orders up to the priesthood, and that they will return to their own diocese and there give perpetual work to the sacred ministry. S. C. Cons., 29 July 1909.

You will resolve: He who swore to an evil thing is never obligated by the oath; indeed he sins in two ways if he fulfills the oath, namely against religion and against the virtue to which the matter of the oath is opposed. S. Th. 2. 2, q. 89, a. 7. He who confirmed a prodigal promise by swearing is not obligated by the oath, because that promise is at least lightly evil. He does not sin against an oath who for the sake of courtesy swore that he would not sit, drink, enter the house, etc., before another, if, compelled by the other, he sits, drinks, or enters first; because for the most part an oath of this sort is null from defect of intention of swearing, or, if it is valid, it is relaxed by the other yielding his right.

Parents who do not fulfill an oath of punishing their children rarely sin, because for the most part the oath concerns a useless thing, or rather inordinate vengeance; add that often those delinquent either have already been corrected, or at least have promised amendment. Likewise merchants for the most part do not seem to be bound by an oath not to sell for less, or many persons not to buy; either because oaths of this sort generally concern a useless thing, or because these men do not have the mind of swearing, or certainly because there is present in the oath a tacit condition, unless things seem likely to turn out better otherwise. L. 176, 180, 185, 186; S. Th. 2. 2, q. 89, a. 7.

How is a promissory oath to be interpreted? - The obligation of an oath is to be interpreted strictly and according to the nature of the act or contract to which it is added, so that it follows all its conditions. The reason is that the one swearing is judged to have wished to oblige himself as little as he could, and otherwise the oath does not change the nature of the act, but superadds to it only the obligation of religion; and therefore it ought to have the same conditions and limitations. Hence he is not bound by oath who under oath promised marriage to a girl rich, healthy, virgin, of good reputation, if she has fallen into poverty, illness, infamy, fornication, because the simple promise then does not oblige. C. Quemadmodum 25, de Iurei. Likewise, if you promised and swore to Titia that you would marry her, you can, leaving her, enter religion, because this tacit condition is present in the promise of marriage: unless I enter religion. And this also holds if betrothals were confirmed by oath, unless the marriage were necessary for legitimating offspring, repairing scandal, or providing for the honor of the betrothed woman, if it could not be met in another way. He who reveals a sworn secret does not sin when the very law of secrecy ceases to oblige, because an oath, as we have said, follows the nature of the act to which it is joined. L. 180, 183, 727; l. 6, n. 870.

What are the tacit conditions included or understood in a promissory oath? - They are: 1. If I shall be able without grave harm, because no one is judged to oblige himself to a thing impossible both physically and morally. 2. If the thing has not been notably changed. 3. If the rights or will of a superior do not stand in the way. 4. If the other has preserved reciprocal fidelity. 5. Unless the other yields concerning his right. L. 180; Struggl 31. Cf. here 566.

Is smallness of matter given in transgression of a promissory oath? - The first opinion denies, because not only a simple promise is violated, but a sworn promise. Therefore in any matter a grave injury is inflicted upon God, whose testimony has been invoked in vain by the one swearing. And indeed God would be called either as guarantor, namely by his authority, or certainly as witness of falsity, if truth were not conformed to the thing promised. For in this oath God is invoked as witness of the present intention, and either as quasi-sponsor or also as witness of future execution. But God can in no way either fail faith or lie in any matter, even the smallest. "Whoever swears that he will do something is obligated to do it, so that truth may be fulfilled," on account of reverence for divine testimony. S. Th. 2. 2, q. 89, aa. 7, 8.

The second opinion affirms, because in a promissory oath God is not properly brought in as witness of the future execution of the thing promised, but only as witness of the actual promise, or of the true intention of executing the promise. Nor indeed is he brought in as guarantor of future execution, but merely as confirming, or furnishing authority to, the obligation which arises from the promise made before him, just as a Prince renders betrothals contracted before him firmer by his authority. Now as to the first, no irreverence is committed against God through transgression of a promissory oath, or God is not made witness of falsity, since we suppose that the promise and the intention of execution were sincere in the one swearing. But as to the other, by infidelity in the matter promised, to be fulfilled under divine authority, irreverence indeed is inflicted upon divine authority, but one which is neither direct and formal, since it is intended only indirectly in the very violation of the promise, nor greater; indeed, with S. Thomas as witness, 2. 2, q. 89, a. 8, per se it is less than the irreverence which is found in transgression of a vow. Since therefore in this, as also in any indirect irreverence against God, lightness of matter is admitted by all, it must also be admitted in that which transgression of a promissory oath inflicts. And indeed if the one swearing, in the act of the oath, had the will of fulfilling, and afterwards does not fulfill it, he does not commit a lie and perjury, but only infidelity, which, since the thing promised is not grave by hypothesis, will not be able to be extended to grave fault. Besides, in this oath God is brought in as witness of the contracted obligation, which consequently cannot be violated without irreverence toward God; but this indeed can be grave or light according to the nature of the matter. St. Liguori, n. 173, says that each opinion is probable; but he adheres more to the second opinion, and in H. A., n. 13, says: "If the thing promised is not grave, infidelity does not reach grave fault." Suarez, l. 3, c. 16, n. 9 seqq.; L. 172, 173, 178, 211.

Does a promissory oath emitted through error or deceit oblige? - R. Negative, if the error or deceit concerns the substance of the thing; but otherwise if it affects only its accidental adjuncts, because a simple contract would be invalid in the former case, but not in the latter. L. 175. Yet the same St. Alphonsus, l. 3, n. 187, warns that the opposite opinion is probable when the error or deceit concerns those circumstances which, although accidental, if they had been known from the beginning, would have deterred one from the oath and promise. Those things entering the quasi-substance of the contract are as a condition without which not. This warning of St. Alphonsus indeed ought to hold, as in vows, so in gratuitous contracts, but not in onerous contracts. Cf. 575.

Does a promissory oath extorted by grave and unjust fear oblige? - The first probable opinion affirms. For the general rule is that any oath is to be kept when it can be done without sin, lest God be brought in as witness of the false. The second opinion, also sufficiently probable, denies, because an oath follows the nature of the act to which it is added. But that promise by natural law is void, or at least rescindable by the very one who suffered fear, according as the promise is gratuitous or onerous, on account of the grave injury which it contains, which is not to be confirmed and continued by oath. Whence even the patrons of the first opinion warn that he who suffered fear can ask relaxation of the oath, so that he may be excused from the obligation of paying; but if he has already paid, he can seek in judgment what he gave, or secretly compensate himself. L. 174; S. Th. 2. 2, q. 89, a. 7 ad 3; q. 98, a. 3 ad 1; Ithur., Cas. 15, nn. 11, 18; Struggl 23, 29.

Must a promissory oath in favor of a third party always be fulfilled, as long as it can be fulfilled without sin? - R. Affirmative, if that third party already has a right acquired through an accepted promise, even if it is against the evangelical counsels, and even if the promise made is void by law in hatred of the creditor, as a promise of paying usuries and a promise of money made to a prostitute, although such an oath was illicit. Understand this if the prostitute, for example, has already furnished her work; otherwise, if not. Yet it must be said otherwise if the promise is void by law because it would be against the common good and concerning a prohibited thing. The reason is that in this second case the fulfillment itself would be illicit. Therefore an oath extorted by fear concerning religious profession, marriage, betrothals, etc., does not oblige. On the contrary, as to the first case, on account of reverence for the divine Name, the oath is to be observed whenever it can be observed licitly. Cf. 554, 558, 560, 566, 970; L. l. 6, n. 870.

312. Principles. I. Every promissory oath concerning a lawful and honorable matter, besides the obligation of justice or of fidelity which arises from the simple promise, also induces an obligation of religion. The reason is that the promise by itself already obliges, and is confirmed and strengthened by the divine testimony invoked. - But an oath concerning an unlawful or entirely useless matter does not oblige in the least; because an oath, as an act of religion, cannot be the bond of iniquity or of an idle matter ¹.

¹ Oaths of this sort do not revive, even if the matter afterward ceases to be idle or unlawful, according to Rule of Law 18 in VI: "That which by law does not subsist from the beginning is not strengthened by lapse of time." Thus he who, contrary to the fidelity of prior betrothals, has contracted a second betrothal under oath, if the prior betrothed woman dies before the wedding, is not to be compelled to the second betrothal, since both the promise and the oath contained an unlawful matter, and therefore were void from the beginning; just as, namely, if a spouse, with the other spouse unwilling or ignorant, professed religion and afterward was brought back from the monastery, when the other spouse has died, he is not to be compelled to the profession of religion, since it had been void from the beginning. For that rule is applied to an oath: "A vow" (and the same reason holds for an oath) "made at an unsuitable time does not oblige at a suitable time." See other examples in Laymann (lib. 4, tr. 3, c. 6, n. 4).

II. The obligation of an oath must be interpreted strictly; and it follows the nature of the act or contract to which it is added, and all its conditions. The reason for the first is that one swearing is judged to have willed to bind himself as little as he could; but the reason for the second is that an oath does not change the nature of the act, but adds to it only the obligation of religion, and therefore it ought to have the same conditions and limitations.

III. The obligation of an oath must also be interpreted according to the tacit conditions included in it or understood under it, which are: 1. if I can without grave harm; 2. if the matter has not been notably changed; 3. if the rights or will of the superior do not stand in the way; 4. if the other party has preserved reciprocal fidelity; 5. unless the other party yields from his right. - St. Alphonsus, n. 180.

314. Q. 3. Whether a promissory oath extorted by grave and unjust fear obliges?

Resp. It is disputed. The first and more common opinion affirms it, because although the simple contract perhaps would be void when viewed according to natural law, yet it is made firm by the oath acceding to it, which must be kept from religion whenever it can be kept without sin. - St. Alphonsus, n. 174, and lib. 3, n. 716. Nevertheless the patrons of this opinion hold with St. Alphonsus that he who has suffered fear can ask relaxation of the oath, so that he may be excused from the obligation of paying; but if he has already paid, he can seek in court what he gave, or compensate himself secretly ⁴. - St. Alphonsus, n. 174, and lib. 3, n. 717.

⁴ If secret compensation is lawful, the obligation of giving even on account of the oath seems futile. For will religion impose a ridiculous obligation, that I place the material act of giving that which by my own authority I can afterward take away and recover, and which the other cannot lawfully receive?

But when the texts of canon law are inspected, by which this obligation from religion is customarily proved, it appears not obscurely that the Roman Pontiffs required that dispensation be sought, not so much because they judged these oaths per se obligatory, as that by this precaution the dangers of illusion and perjury might be met, as also the reasons for this economy adduced by Reiffenstuel (lib. 1, tit. 40, n. 59) insinuate.

The second opinion, which seems sufficiently probable, denies it; because an oath cannot confirm a promise void by natural law. For an oath follows the nature of the act to which it is added. See what is to be said in the tract On Contracts in General.

Q. 4. How does the obligation of an oath cease?

Resp. 1. It ceases from within ⁵, just as law does, by cessation of the motive cause, etc.

⁵ This happens 1. because of a notable change of matter; concerning which St. Alphonsus (lib. 3, n. 187) admits the rule handed down by the Salamancans (tr. 17, c. 3, n. 22), that what, if it had been known from the beginning, would have prevented the vow or oath from being made, liberates from the obligation of the vow or oath; you have examples below in the third resolution; 2. because of the cessation of the final cause, for example if by oath you promised alms to Paul as poor, and he becomes rich (St. Alphonsus, lib. 3, n. 188).

Resp. 2. It ceases from without by irritation, commutation, and dispensation, just as a vow does, of which we shall speak in the following chapter ⁶. It ceases also by relaxation or remission of the obligation made by him in whose favor the sworn promise was emitted, because anyone can yield his own right.

⁶ These words of Suarez (De Voto, lib. 6, c. 14, n. 6) are to be noted: "It is sufficiently probable that delegated power simply to dispense in vows extends to dispensing in pious oaths concerning the same matter, when they stand by themselves and produce only their own obligation. This is the common opinion, and without doubt it can be observed in practice." To this doctrine the Salamancans (tr. 17, c. 3, n. 3), whom St. Alphonsus followed (lib. 3, n. 190), incautiously oppose certain authors, as, for example, Sanchez, who in reality were not treating of an oath alone, nor even of sworn vows, but of an oath which does not depend on a vow emitted concerning the same matter.

But concerning this case the same Suarez says (l.c., n. 19): "Even if the vow and the oath immediately fall upon the same matter, and each obliges by itself to the honor of God, by an absolute faculty of dispensing in vows either the vow, or the oath, or both can be removed at the discretion of the one dispensing. For this assertion we can allege all the authors of the first," that is, the preceding, "assertion... and other modern and learned men hold it."

*Against this note the VV. fight through twelve columns (pp. 269-275), and directly establish against it this thesis (p. 270): "The authors cited by St. Alphonsus with the Salamancans for the negative opinion are rightly alleged by them." - Resp. In the Note it is written that certain authors are alleged without cause, not all. With this premised, it must be added that the thesis proposed by the VV. would have to be called false if anyone should detect even one writer wrongly alleged. But the VV. themselves concede (p. 272) that Sanchez stands not for the negative opinion with St. Alphonsus, but for the affirmative. Therefore. And in reality Sanchez (Decal., lib. 4, c. 53, n. 8-9) writes: "The third opinion says that delegated faculty for the dispensation or commutation of vows extends to the dispensation and commutation of oaths which are made to God alone... And this opinion has truth, although the oath does not have a promise included, but is made without it to God alone."

But next Bonacina too must be added to Sanchez. The reason is that one question is that of which Bonacina treats, while another is that of which the Salamancans treat, and after them St. Alphonsus. Among the Salamancans the question is (tr. 17, c. 3, n. 3): "Whether if to someone faculty is granted of dispensing or commuting vows, by this very fact faculty is judged granted of dispensing or commuting whatever oaths have been furnished to God alone." But St. Alphonsus says (lib. 3, n. 189): "It is asked whether he who has delegated faculty of dispensing in vows can dispense in oaths"; and that the sense of each question is the same is clear both from the context of St. Alphonsus and from the allegations which the holy Doctor transcribes from them. But Bonacina has it otherwise (De 2 Praec., disp. 4, q. 1, punct. 17, n. 12): "There is doubt whether those commuting vows from faculty delegated to them can also commute oaths annexed to such vows." But this latter question, by the consent of all the doctors, is plainly diverse from the former. Therefore. And indeed it was to be wished that in reporting Bonacina's opinion on this question the VV. had not omitted the final words. "Each opinion," Bonacina writes, "is probable; but the first seems more probable to me." Here the VV. stop. But Bonacina adds: "especially in a promissory oath; for this is not a vow, since it is not made to God, but to man." These words show that Bonacina affirmed this from an entirely different reason.

Besides, not all will easily concede what the VV. hold as certain, namely that the reason is invincible on account of which St. Alphonsus, after he had said concerning the question proposed by himself that each opinion was probable, that is, both the negative and the affirmative, then concludes that the first, negative opinion must altogether be held, because the obligation of an oath already contracted, since it is certain and possesses, cannot be removed by a dispensation only probably valid. Someone, arguing ad hominem, could say that both sins and censures are certain, but remission or absolution uncertain when the jurisdiction of the confessor is only probable; therefore etc., etc.; which conclusion St. Alphonsus, as is known, does not admit.

315. Resolves. 1. He who has sworn an evil matter is never obligated by the oath; indeed he sins in two ways if he fulfills the oath, namely against religion and against the virtue to which the matter of the oath is opposed. - St. Alphonsus, n. 176.

2. He is not obligated by an oath who has confirmed a prodigal promise by swearing, because that promise is at least lightly evil. - Thus Suarez, the Salamancans, and others commonly with St. Alphonsus, who admits this as more probable, n. 185 ⁷.

⁷ Yet do not conclude from this that he is not bound to that in which no prodigality appears. Make an exception, unless the promised thing is indivisible.

3. He is not obligated by an oath who, under oath, promised marriage to a girl who was rich, healthy, a virgin, and of good reputation, if she falls into poverty, infirmity, infamy, or fornication; because the simple promise then does not oblige. - St. Alphonsus, n. 180.

4. He does not sin against an oath who for the sake of courtesy swore that he would not sit, drink, enter the house, etc., before another, if, compelled by the other, he first sits, drinks, or enters; because for the most part an oath of this sort is null from defect of intention of swearing; or, if it is valid, it is relaxed by the other. - St. Alphonsus, n. 180.

5. He does not sin who reveals a sworn secret when the law itself of the secret ceases to oblige; because an oath, as we have said, follows the nature of the act to which it is joined ⁸.

⁸ Hence St. Alphonsus says (lib. 3, n. 183): "Oaths about keeping a secret, which are furnished in congregations concerning elections or other things, oblige gravely or lightly according to the harm which they can bring." Moreover those things must be observed which the same St. Alphonsus (ibid., n. 180-181) has concerning an oath by which someone obliges himself to observe the decrees and rules or statutes of some congregation, university, chapter, etc. Namely he proposes these rules after the doctors: 1. The oath is understood of statutes already published, but not of those to be published; 2. It is judged to oblige under grave or light obligation, or under penalty only, or only under counsel, according as, namely, the statute obliges; 3. It does not oblige to those things whose obligation is not in force because of impossibility or desuetude; and this holds even if an oath is furnished concerning some particular statute of that sort; 4. Finally, it does not oblige when some statute is not observed by the greater part of the community or college.

6. Parents rarely sin when they do not fulfill an oath of punishing children; because for the most part the oath concerns a useless thing, or rather disordered vengeance; there is added the fact that the delinquents either have already been amended, or at least have promised amendment. - St. Alphonsus, n. 180.

7. Merchants also, for the most part, do not seem to be bound by an oath not to sell for less, or not to buy for more; either because oaths of this sort are for the most part about a useless thing, or because these men do not have the mind of swearing, or certainly because there is in the oath a tacit condition: unless matters seem to turn out better otherwise. - Thus more commonly. - See Cases, n. 296 and following.

793. • It is asked, 2. Whether oaths extorted by fear are valid for strengthening contracts invalid of themselves because of fear?

I reply. A twofold probable sentence is given:

The first, more common sentence affirms, because from the motive of Religion the oath must be observed whenever it can be observed without sin. - St. Lig., De Iuram., n. 174. - Lugo, Billuart.

The second probable sentence denies, because the oath ought to follow the nature of the act; for an oath cannot confirm an act null by nature. Besides, the oath would be an act wholly useless, indeed ridiculous. For, e.g., after the handing over of money made by you to a robber by force of the oath, you could immediately recover the same money from the robber, even by employing force; which would be wholly illusory. - St. Antoninus. - Sanchez, etc.

953. Here there is question only of a promissory oath; for an assertory oath produces no obligation for the future, since it consists in the mere affirmation of some thing. - Every promise induces an obligation of justice or fidelity, according to the principles set forth in the Treatise on Justice, n. 677; when an oath accedes to this, it produces a new obligation of religion: of which we must now speak.

954. 1. The existence and gravity of this obligation: A promissory oath, concerning an honest thing, induces an obligation of religion, grave from its genus, for the one swearing. For the one swearing invokes God not only as witness of the promise, but also as guarantor of its execution; and therefore, from reverence toward God, he is bound to execute what was promised. - Nevertheless, he who utters the formula of an oath without the intention of swearing, whether from inadvertence or from deliberation, does not contract an obligation: say the same of him who does not have the intention of obliging himself; for in both cases one of the elements necessary either for an oath or for contracting an obligation is lacking.⁴

⁴ But what obligation is incumbent on him who emitted a promissory oath in favor of a third party can be inferred from what was said in the Treatise on Justice, n. 621.

(a) Moreover, the gravity of the obligation depends on the gravity of the thing promised; for since the one swearing is judged to have had a sincere will of fulfilling what was promised, he sins only insofar as he does not put the same into execution; but if the thing promised is of slight moment, its non-execution cannot be grave; for an oath does not change the nature of the act, but only adds to it an obligation of religion.

(b) The obligation of a personal oath belongs to the one swearing, and therefore does not pass to heirs, while the obligation of justice or fidelity arising from the promise itself can be real and can pass to heirs (De Justitia, n. 679).

955. (c) An oath concerning an impossible, illicit, or plainly useless thing induces no obligation. For no one is held to the impossible; besides, an oath cannot be the bond of iniquity, or even of a vain thing, which in no way turns to the honor of God. If the thing afterward becomes licit or useful, an oath which was null from the beginning does not revive: for that which by law does not subsist from the beginning is not made firm by the passage of time.⁵

⁵ Rule of law 18 in the Sext.

(d) From the Code, can. 1317, "an oath extorted by force or grave fear is valid, but can be relaxed by an ecclesiastical Superior." Nevertheless, from can. 1318, "a promissory oath follows the nature and conditions of the act to which it is added. If an oath is added to an act directly tending to the harm of others or to the prejudice of the public good or of eternal salvation, the act consequently obtains no firmness."

956. 2. Concerning the extension and interpretation of this obligation.⁶ (A) The general principle is that the obligation of an oath does not extend more widely than the promise itself to which it accedes; for an oath is something accessory to the promise itself, which it confirms; but it is fitting that the accessory follow the nature of the principal.⁷ - Except if the one swearing intended the matter otherwise; for the extension of the obligation, like its existence, depends chiefly on the intention of the one swearing.

⁶ In the Treatise on Justice, n. 662-664, there is weighed what sort of obligation an oath adds to a contract.

⁷ Rule of law 42 in the Sext.

(B) Moreover, two particular rules are to be noted: (a) The obligation ought not be extended beyond the sense of the words strictly accepted. For hateful things are to be restricted; but an obligation which arises from an oath is judged hateful, as restricting liberty. Besides, an oath depends on the intention of the one swearing; but he is not judged to will to oblige himself beyond the expressed and strict sense of the words.

(b) A promissory oath is to be interpreted according to the conditions and restrictions which are understood from the nature of the matter, or from the principles of law, or from the common sense of prudent men. Moreover, the chief restrictions of this kind are the following: - if I am able, physically and morally; - without prejudice to the right of superiors, who from a just cause can invalidate the obligation or dispense in it; - if the matter has not been notably changed: for if it is notably changed, the intention of the one swearing did not extend to it; - if the other has kept faith: for in vain does someone ask that faith be kept toward himself by him toward whom he himself refuses to keep the faith pledged;⁸ - unless the other cedes his right: for since a promissory oath is made in favor of another, and this other can renounce his right, it is in some way subjected to his will; - unless there is a grave reason for changing the proposal: for if execution cannot take place without a grave danger of death, infamy, etc., not foreseen before, the one swearing is not judged to have willed to oblige himself.

⁸ Rule of law 75 in the Sext.

957. Corollaries. (a) An oath of observing the statutes of some college, congregation, office, etc., ought to be understood of statutes already issued, not of those to be issued, - of those which then are in force, not of those which have fallen into desuetude or are not observed by the greater part of the community, - and indeed in that manner in which the statutes oblige, that is, under grave sin, under light sin, or only to a penalty, according to the statutes themselves: for an oath does not change the nature of the obligation, but only adds to it the bond of religion.

(b) An oath of observing a secret does not oblige when the obligation of the secret itself ceases (De Justitia, n. 421-425).

(c) An oath of fidelity and obedience to some Prince or Government, or of observing a Constitution, does not oblige except according to the common sense of honorable men; accordingly it does not oblige one to embrace in mind all things which are contained in the Constitution, but only to undertake nothing illegitimately against the same.⁹

⁹ Bouquillon, op. cit., n. 660-714, discusses learnedly the various political oaths.

(d) An obligation induced by oath ceases: by the cessation of the end, - by condonation made by him in whose favor the oath was uttered, - by invalidation, or dispensation, or commutation, according to the principles set forth below, n. 990 sq.

What is contained in that oath. As is proved by the very notion, a promissory oath regards the truth both of the present intention and of the future fulfillment. God is called as witness of the present intention; wherefore, under this respect, a promissory oath does not differ from an assertory oath. As to future fulfillment, the interposition of divine authority has this effect, that from reverence toward God, and therefore from the virtue of religion, the one swearing must fulfill what he promises or proposes. Thus the ratio is shown to be akin to a vow; yet because the promise itself is not made directly to God, it recedes from the nature of a vow, and its violation is less grave than the violation of a vow (2, 2, q. 89 art. 8). At the same time the notion of an oath carries this with it, that God is called upon as witness, not indeed of future truth - for, since impediments can arise, that, at least absolutely, cannot be done - but that He is called upon as witness of constancy. But because constancy is not desired in him who is lawfully impeded or dispensed, nothing is done against the oath by one whom either excuse assists. And because God is the avenger of perjury, both notions composed together, i.e., of constancy owed from reverence toward God, and of the invocation of God as witness of that constancy, have the effect that a certain security concerning the execution itself is obtained through a promissory oath. This security can be called a divine quasi-suretyship.

Thus we seem able to reconcile the three modes by which a promissory oath as such is conceived: a) God is invoked as witness of future truth (cf. 2, 2, q. 89 art. 7); b) the faith itself is bound to God, so that you are bound almost from a vow (d'Annibale, II, 25); c) God is called metaphorically a quasi-surety, insofar as the intention of doing can no longer be changed without irreverence offered to God, and that invocation of God supplies a certain security of execution (most authors after Suarez, Rel., Tr. 5, Lib. 3, c. 16, n. 10-13).

The Code, c. 1317, simply has these words: "He who freely swears that he will do something is held by a peculiar obligation of religion to fulfill what he has confirmed by oath."

That oath can accede to a simple purpose, which then must be observed from reverence toward God; or to a promise obliging from fidelity, which then, from the same reverence, must be observed more carefully; or to a vow, so that a double obligation of religion has arisen; or to a contract already of itself obliging from justice: in which case a right has been acquired by the third party and fortified by the protection of religion.

The sworn fulfillment of a contract. The parties can be moved by a twofold intention to swear to the fulfillment of a contractual promise, or a promise obliging of itself from justice. Either, thinking the promise valid, they intend merely to increase the obligation already undertaken by the obligation of religion; then, from the very intention of the parties, the oath must follow the nature of the act; or, conscious of a defect or vice, they will to substitute an obligation of religion in the place of an obligation of justice; and then, unless from the nature of the thing or from the prohibition of law the object of the oath is illicit, an obligation of religion arises from the oath; and, unless positive law or harmful circumstances have introduced more, this alone binds the parties.

N. B. Formerly, an oath having been added, agreements had to be judged in the ecclesiastical forum; and acts which otherwise would have been destitute of action were confirmed civilly.

"An oath extorted by force or grave fear is valid, but it can be relaxed by a Superior" (can. 1317 § 2). For the Church did not will to invalidate such an oath, lest, by alleging the excuse of fear, too frequent an occasion of perjuring be given (Keiffenstuel in L. 1, t. 40, n. 58. 59). - An oath extorted by error or fraud will be valid or not, according as the error affected only circumstances of lesser moment or was substantial.

An oath of doing a bad thing, or a vain thing, or a useless thing, or a thing directly contrary to the evangelical counsels, or something so indifferent that it is made honest neither by the end nor by circumstances, produces no obligation. For an oath cannot be a bond of iniquity, or bind us to vain and idle things, since obligations of this kind impede greater goods.

Wherefore, canon 1318, § 2 warns us that acts which tend directly to the harm of others or to the prejudice of the public good or of eternal salvation acquire no force from an oath.

Yet a valid promise or agreement can be confirmed by oath, by which someone is prohibited from taking, or rather professing, the way of the evangelical counsels, at least for a time or without Pontifical dispensation. Cf. n. 200.

The oath of a minor. Although, from c. 1317, an oath furnished neither by force nor by fraud, by which someone renounces a private good or favor conceded to him by law, must be observed as often as it can be observed without sin, that must be understood insofar as the one swearing is capable of such renunciation. Wherefore, if a minor, still a minor, has sworn that he would not rescind a void or rescindable agreement made by him, since our law, in view of the common good itself, renders that confirmation void, he seems strictly to need no dispensation. And indeed a dispensation, if it seems to have to be given, removes no acquired right, so that it can be granted by any suitable priest. If, I say, it seems to have to be given, because any priest can declare the emptiness of the act.

He swears feignedly or simulatedly who either inwardly dissents in mind from the words which he utters, or does not will to undertake the obligation of religion. Concerning this matter there is proposition 25 condemned by Innocent XI: "with cause it is lawful to swear without the intention of swearing, whether the matter is light or grave."

And in reality that fiction contains a lie with vain usurpation of the name of God. This is of itself venial; but it would become grave: a) in contracts about a grave matter, because of fraudulent deception; b) when from a grave precept, as in a legitimate judgment, an oath is imposed: then one would be pressed at least by the obligation of religion; c) when one thus swears feignedly without the intention of fulfilling: because, since the name of God is invoked exteriorly, this character of exterior perjury is injurious to God almost as exterior blasphemy is. So rather with Suarez, Rel., tr. 5, L. 3, c. 17, n. 3. 4, than from the subtle reason of Sanchez, Decal. L. 3, c. 6, n. 8-11.

But when the stain of lying is absent from the fiction, as when it is requested unlawfully in circumstances which exclude a serious and sincere action, a feigned oath seems able to be excused by a grave cause. Cf. Lugo, Paen. d. 16, n. 211; Lehmk. I, 556.

A feigned and invalid oath introduces no obligation of religion as such. Yet easily, to prevent scandal or harm, it will have to be executed.

He who, terrified by the threats of a robber, has sworn that he will give him a sum of money, although, because of the rescindable contract, he is held by no obligation of justice, must and can be dispensed from the oath (c. 1317 § 2): which was controverted before the Code ¹; but he could also pronounce the words without the intention of swearing, so that the oath itself is null. But if the contract is null, for example because it is invalidated by civil law, then relaxation of the oath seems superfluous.

¹ Cf. e.g. Lehmk., I, 564. St. Thomas follows the severe opinion, 2, 2, q. 89 art. 7 ad 3.

He who, in favor of someone or of certain persons, has absolutely sworn that he will furnish something, so that, for example, from their consent a right has been acquired by them, is held to fulfill it as long as it is honorable, even if it impedes a better good, for example entrance into religion. Nor can he himself commute that oath into something better, but he must seek a dispensation. Hence is also explained c. 542, § 1, which declares invalid the reception into the novitiate of a candidate who is bound by an oath by which, for a definite time, he is held, by institution of the Holy See, to a mission or diocese. But in similar oaths there is easily understood the condition, "unless I shall have been called to the state of perfection." Cf. Lugo, Iust. d. 21, n. 67. 73; Nilles, De libertate clericorum religionem ingrediendi, n. 43. 44 and p. 120. 121. Wherefore, in the oath of a mission, an express promise is made of not entering religion without dispensation of the Holy See.

A promissory oath must be interpreted in the same way in which a promise not sworn would be explained. Wherefore, one who swears that he will observe the decrees and rules or statutes of some congregation, university, or chapter, is judged to have sworn not so much the statutes themselves as due subjection to those laws. Wherefore that oath is understood: a) of statutes already issued, not to be issued; b) as long as and insofar as they are in force by use; c) under grave sin, under light sin, under counsel, under penalty, according as the thing itself or the law in force demands it.

Concerning interpretation c. 1321 has this: "An oath must be strictly interpreted according to law and according to the intention of the one swearing, or, if he acts fraudulently, according to the intention of him to whom the oath is sworn." This is a most apt rule of the external forum (1). The intention of him to whom the oath is sworn will have to be gathered from the circumstances or from another demonstration. In the internal forum, the obligation of the oath does not exceed the intention of the one swearing. Yet the one swearing will have to repair the harms of harmful fraud.

An oath concerning civil constitutions does not affect laws contrary to divine or ecclesiastical law. If laws of this kind are brought forward or urged, a clause excluding them must be added to the oath. But if they lie as though buried, the oath is now of itself judged reasonably circumscribed by laws properly in force. Cf. Lehmk. I, 568.

The obligation of fulfilling a promissory oath is certainly grave if the object itself of the promise must be considered grave. But if it is light, grave authors, such as Lessius, Iust. etc. b. II, c. 42, dub. 5, judge the obligation to be under mortal sin, because God is invoked as witness of falsity. Lessius, however, concedes the probability of the more benign opinion, which Suarez then confirmed by his authority, Rel. tr. 5, Lib. 3, c. 16, n. 15-19; because a lie would be lacking if, when it was sworn, the intention of fulfilling the promise had been had, so that God was merely the surety of a light obligation. Yet we confess that, for the reasoning of the Excellent Doctor to be apodictic, it is necessary that you wholly omit that which seems sufficiently to cohere with the nature of an oath: that God was invoked as witness of constancy. More easily, although Suarez does not admit this, l. c. n. 8, we shall concede with most authors that one sins lightly who has omitted a moderate part of a grave object promised, because God was assumed as witness of substantial constancy, not of perfect constancy. But practically, in no light matter will the obligation of a sworn promise have to be urged under grave sin.

From c. 1319 itself, the obligation introduced by a promissory oath ceases: by remission proceeding from him for whose advantage it was sworn; - by substantial change of the thing, or if, the circumstances having been changed, the thing becomes bad, wholly indifferent, or impedes a greater good (here, however, as was said above, acquired rights must be attended to); - when the final cause, or the condition under which perhaps the oath was given, is lacking: for example, when the poverty of him to whom you had promised alms ceases, or when he dies for whose health you had promised a pilgrimage; - by irritation, dispensation, commutation. Moreover, all who can relax vows are permitted by canon 1320 to remove oaths also, by the same reason and in the same way.

Preliminary note. The promissory oath must be treated specially, because it differs from the assertory in this, that it not only asserts something concerning the present, but besides affirms something concerning the future, namely accurate execution of the thing promised.

614. PRINCIPLES. I. A promissory oath concerning a licit and useful thing induces an obligation of religion. For through an oath God is invoked not only as witness of truth in promising, but also as surety for faithful execution of the thing promised. Therefore oath truly induces an obligation of executing what was promised, on account of reverence for the divine name, or an obligation of religion (cf. Lehmkuhl, I, 562, note; Schindler, II, p. 165).

It was said: 1. An oath concerning a licit thing, etc.; because if it is concerning an illicit thing, or a thing of no utility, it induces no obligation. For an oath, as being an act of religion, cannot be a bond of iniquity, or of an idle thing which does not fall to the honor of God. Indeed, he sins gravely who promises illicit things by swearing. But neither does an oath become valid, even if such an illicit and vain thing, the circumstances afterward being changed, becomes honorable; since that is not strengthened by lapse of time which did not subsist in the beginning (III, 176).

But if the thing promised is less good and against the evangelical counsels, one must distinguish: either the promise was made to God alone, or for the utility of a man. In the first case there is no obligation, because the thing promised to God ought not to be impeditive of a greater good: thus, for example, he who had sworn that he would never fast outside the days established by the Church can nevertheless fast. - In the second case, if the promise was accepted and can be kept without sin, the oath must be stood by. The reason is that any promise concerning a licit and possible thing, and useful to a third party, must be fulfilled at least from fidelity (cf. n. 1062). Thus, for example, he who swore to a girl that he would enter matrimony with her is held to accept her as wife, unless he wishes to enter Religion: which is conceded to him from a special disposition of law (III, 173; H. Ap., V, 13). Thus also a priest who swore that he would not leave the diocese cannot, without dispensation, enter Religion (III, 177).²

2. It induces an obligation of religion. Here it must be noted: a) He who violates this obligation by not fulfilling what he swore does not indeed commit perjury strictly so called, but sins by irreverence toward God, by despising his authority, which had been brought forward for strengthening the promise. b) The obligation which arises from an oath, since it is an obligation of religion, is altogether personal and does not pass to heirs. Wherefore these persons, indeed by force of the oath and from religion, are not held to fulfill it, even if perhaps they are held by another title, for example from pact and justice. c) A fictitious oath does not induce an obligation of religion, since it is null; nevertheless it can well oblige so that scandal or harm to another may be avoided (III, 172, 177).

II. A promissory oath obliges under grave or under light matter, according to the gravity of the thing promised. The obligation of an oath is ordinarily less than the obligation of a vow; but a vow, in light matter, obliges only under light matter. St. Thomas, 2.2, q. 89, a. 8; Lehmkuhl, I, 562. See St. Alph., III, 173; Vind. Alph., I, p. 227.

III. A promissory oath has the same condition and the same mode of interpreting as the promise or purpose to which it is annexed. The accessory follows the principal; and therefore when the promise does not oblige, neither does the oath attached to it oblige (III, 180).

615. Since therefore an oath claims for itself the same conditions and mode of interpreting as the promise to which it is added, this TWO-FOLD RULE can be established:

RULE 1. The obligation of an oath is of strict interpretation, namely so that the one swearing is considered to have wished to oblige himself as little as he could. For thus promises and contracts must be interpreted.

Therefore, if some act or contract does not subsist from the beginning, whether because it is invalid by its nature, for example because of equivocation employed in promising or in contracting, or because it is void from positive law on account of the common good, it follows that no obligation comes from the oath either. Thus an oath extorted by fear does not oblige concerning profession, matrimony, espousals, renunciation of the ecclesiastical forum, donation made by a cleric to a concubine (III, 177).

RULE 2. Every oath must be interpreted according to the CONDITIONS which, by fiction of law, are tacitly understood.

But they are the following: a) If I shall be able, that is, if the promise can be fulfilled without grave harm. b) Saving the right of the Superior, that is, if the Superior does not prohibit execution. c) If the state of things has not been notably changed. d) If the other part also has kept faith in a mutual obligation. e) If the promisee does not yield his right. f) If the final cause, on account of which the promise was made, does not cease (III, 180, 187; H. Ap., V, 18).

616. From these things you will deduce: 1. An oath of observing the statutes of some congregation, college, etc., is to be interpreted thus: a) that it is understood concerning statutes published, not to be published; b) that it is understood to oblige under grave or light matter, or only to penalty, or only under counsel, just as the statute itself obliges; c) that it does not oblige to statutes which have lost the force of obliging, on account of impossibility, or desuetude, or because they have thus been received in use; d) that it also does not oblige if some statute is not observed by the greater part of the community (III, 181). - Religious profession also, if it is invalid, is not strengthened through an annexed oath.

2. "He who swore that he would preserve a secret does not sin against the oath by revealing it when he cannot conceal it without grave harm to himself or another; because the very promise of secrecy does not seem to oblige except with this condition: if it does no harm. Similarly, the obligation of the oath ceases if the matter has become known from elsewhere" (III, 183).

3. He who swore to a judge that he would say the things which he knows is not held to reveal hidden things, because at least half-full proof of the crime must precede. Yet except cases which commonly do not admit except single witnesses, as, for example, the case of solicitation to shameful things (ibid., 5).

4. He who promised with an oath that he would return to prison, much more probably is held to return with probable fear of death or of most grave unjust harm; because, the promise having been posited, to return is a work of virtue. Yet others deny, because it would be an evil action voluntarily to offer oneself to death (cf. III, 186).

5. "Parents or masters swearing that they will punish children or servants rarely sin if they do not fulfill the oath; either because the delinquents have already been corrected, or because the oath was concerning a useless thing, or rather concerning disordered vengeance; or because such oaths are very often made without an intention of swearing, but only of frightening" (ibid.).

6. Generally, the oath not to sell for less or not to buy for more does not bind merchants; either because oaths of this sort are for the most part concerning a useless thing; or because these men do not have the intention of swearing; or certainly because there is in the oath a tacit condition, unless things seem to go better otherwise.

7. An oath of fidelity and obedience regards only those things which are comprehended in the office of the one swearing. Whence, by force of such an oath, an inferior cannot be held either to illicit things, or to impossible things, or to things too grave, or to things extrinsic to his office. See Lehmkuhl, I, 568. Cf. what was said n. 611, 4.

617. Questions. QUES. 1. Whether an oath ever obliges by which a promise void by law or to be voided at the discretion of the one promising is confirmed?

Resp. 1. It obliges if the promise is made void in favor of the one promising, and he, conscious of the matter, nevertheless swears. For one acting thus renounces his right and binds himself with the bond of religion, which, although it confers no right upon the promisee, ought to be kept on account of reverence for God. 2. It does not oblige if the promise is made void on account of the public good, because the thing promised then becomes illicit; nor does it oblige if the one swearing intends only to bind himself, by the bond of religion, to the proper and connatural obligation of the promise (III, 172, 3; 177). Cf. below n. 1059.

QUES. 2. Whether an oath emitted from deceit or ERROR obliges in conscience?

Resp. 1. It does not oblige, if the error or deceit turns upon the substance of the thing, or essential circumstances, or other circumstances sufficiently notable, which, if they had been foreknown, would have impeded the promissory oath; because then the thing promised is not considered sufficiently known for consent to be free. 2. But it obliges if the error or deceit turns upon circumstances altogether accidental (III, 175). - See n. 1061 ff.

QUES. 3. Whether an oath extorted by GRAVE and UNJUST FEAR obliges?

Resp. 1. In the EXTERNAL forum, where the mind of swearing is presumed to have been lacking, it certainly does not oblige. - 2. As regards the INTERNAL forum, it is disputed; but the more common and far more probable opinion, which also D. Thomas embraces with Suarez and Lugo, says that it obliges. Thus, for example, the oath of giving money or usury to a robber or usurer obliges. And the reason is that from religion we are held to effect that what we swear be true, lest we make God witness of falsity. The rule of law is consonant, according to which any oath whatsoever must be kept which can be kept without sin.³

Nevertheless: a) One suffering fear can swear with mental restriction, so that he contracts no obligation (n. 608, q. 2 and 615, Rule 1). b) If he truly promised, he can seek relaxation of the oath from the Bishop, or from another having faculty, so that he may be excused from the obligation of paying. c) If he has already paid, he can seek again in judgment what he gave, or compensate himself secretly (cf. n. 1059, q. 2). See St. Alph., III, 174; ed. G., I, 480.

The adversaries indeed say that a payment which can be sought again or secretly taken back is something ridiculous. But St. Alphonsus responds that the payment is not illusory, because there is always danger lest the thing handed over to the thief from fear cannot afterwards be sought again.

Note. 1. The obligation of an oath ceases intrinsically by cessation of the motive cause, that is, when the matter of the oath becomes either impossible, or useless, or harmful, or when a notable change or circumstance supervenes, which, if foreseen, the oath would not have been made (cf. n. 615, Rule 2; 625, 4).

2. It ceases extrinsically by irritation, dispensation, and commutation, just as a vow, because the same reason runs. It also ceases by remission of the obligation made by him in whose favor the sworn promise was emitted, because each one can yield his own right (III, 187-193).

448. Preliminary. In treating of the obligation of an oath, the discourse is principally about a promissory oath. For although an assertory oath, in the very act of swearing, strictly requires and obliges that the truth be spoken, since otherwise the most grave sin of perjury is committed, nevertheless, once an assertory oath has been duly taken, no other obligation remains. Certainly a grave obligation can arise to repair damage caused by a false or unjust assertory oath, but such an obligation arises only accidentally, namely, from the abuse of the oath; and it is not proper to an oath, but common to every unjust action. It remains, therefore, that only the obligation of a promissory oath be treated. This obligation is twofold: 1. the one swearing must, in the act of swearing, have a sincere will to fulfill the things promised; 2. the one swearing must, at the established or opportune time (if no time was established), actually fulfill the things which he promised by oath. In order, we treat: 1. of the obligation itself of a promissory oath; 2. of the interpretation of this obligation; 3. of the cessation of this obligation.

1. Existence of the obligation.

449. Principle. a) A promissory oath clothed with the due conditions binds, from the virtue of religion, only the person swearing to those things which were sworn. b) This obligation is grave or light according to the gravity of the matter promised.

Explanation. a) That a promissory oath clothed with the due conditions binds in conscience is easily proved both from Sacred Scripture and from reason. "Thou shalt perform thy oaths to the Lord."⁵⁶¹ "If any man vow a vow to the Lord, or bind himself by an oath, he shall not make his word void, but shall fulfill all that he promised."⁵⁶² The reason is added: By swearing, a man invokes God as though the guarantor of the execution of the thing promised. But it is a great irreverence inflicted upon God if someone culpably does not keep such a promise, since this is contempt and disparagement of God as witness. An oath, as a personal act causing a personal obligation, binds from the virtue of religion only the person swearing;⁵⁶³ therefore it cannot validly be taken through a proxy, at least in ecclesiastical law.⁵⁶⁴ Therefore the same things also apply which were said above in n. 402 concerning the obligation of a vow.

One who violates a simple promissory oath commits one sin, namely, irreverence toward God. One who violates a sworn vow commits two sins, namely, a sin of irreverence because the oath is violated, and a sin of infidelity toward God because the vow is violated. For although both the violation of an oath and the violation of a vow are against the same virtue of religion, nevertheless in each there is a specifically diverse malice, since in such an oath the invocation of divine testimony is violated, but in a transgressed vow the fidelity promised to God is violated. One who violates a sworn pact likewise commits two sins: one against religion, the other against justice. Finally, one who violates a vow with a sworn pact commits three sins because of a threefold violation, namely, of the vow, the pact, and the oath.

You ask: Which obligation is more grave (other things being equal), that of a vow or of an oath? Other things being equal, the obligation of a vow seems to be more grave, since it binds from fidelity toward God; but a promissory oath binds rather from reverence toward God as the guarantor invoked. Fidelity, moreover, seems to be a stricter obligation than simple reverence, since every infidelity contains irreverence, but not conversely.⁵⁶⁵

⁵⁶¹ Matt. 5:33.

⁵⁶² Num. 30:3.

⁵⁶³ S. theol. 2, 2, q. 98, a. 2 ad 4.

⁵⁶⁴ Cf. Code of Canon Law, c. 1316, § 2.

⁵⁶⁵ S. theol. 2, 2, q. 89, a. 8.

450. b) The second part of the stated principle is greatly disputed. All indeed teach that it is a grave sin of perjury if someone culpably does not render grave matter promised by oath; but several distinguished authors, such as Cajetan,⁵⁶⁶ Lessius,⁵⁶⁷ Valentia,⁵⁶⁸ and especially Concina,⁵⁶⁹ think that there is no slightness of matter in the violation of a valid promissory oath, because every violation of an oath is perjury and every perjury is a mortal sin. These authors admonish, however, that they speak only of valid oaths made with serious deliberation, and not of those which are made without serious deliberation or an intention of swearing. Hence even they concede that mothers do not sin mortally who promise children under oath an apple which they nevertheless do not afterwards actually give; on the contrary, they say that he sins mortally who seriously and deliberately swore that he would give one obol and afterwards culpably refuses this obol.

The far more common and more probable opinion admits slightness of matter in the violation of a promissory oath. Certainly, if someone swearing from the beginning did not will to execute the oath even in light matter, there is a mortal sin of perjury, not indeed because of the matter itself to be rendered, but because of a lie confirmed by an oath. But then not only the promissory oath but also the assertory oath is violated; for this man asserts under oath that he wills to give this light matter, and in reality he does not will this. Therefore such a one swearing invokes God as witness to a lie; this is a grave irreverence and consequently a grave sin. But that there is slightness of matter in the violation of a promissory oath is already inferred from the fact that the obligation of a promissory oath is less than the obligation of a vow, as was said above from the Angelic Doctor. But in the violation of a vow there is slightness of matter, as all concede. Therefore, a fortiori, there is slightness of matter in the violation of a promissory oath. Moreover, as St. Thomas⁵⁷⁰ says, "one who promises something, if he has the intention of doing what he promises, does not lie, because he does not speak contrary to what he bears in mind; but if he does not do what he promises, then he seems to act unfaithfully by this, that he changes his intention." But infidelity certainly admits slightness of matter, so that in a small thing it is not a grave sin. St. Antoninus,⁵⁷¹ St. Alphonsus,⁵⁷² Dominic Soto,⁵⁷³ John of St. Thomas,⁵⁷⁴ Sylvester Prierias,⁵⁷⁵ and almost all modern authors⁵⁷⁶ defend the proposed opinion concerning slightness of matter in a promissory oath as probable or even as more probable.

Hence, if someone swore to observe the statutes of some college, chapter, or University, and afterwards violated some small statute, he sins only venially; if someone swore that he would no longer drink wine, and afterwards took a little, he does not sin gravely. But what is slightness in the violation of a promissory oath? The same things are to be said as were established above in n. 405 for the violation of a vow; indeed, since an oath, other things being equal, does not bind as strictly as a vow, the matter of transgression in it can be increased somewhat before a grave sin is reached.

⁵⁶⁶ Cajetan (in his Summa, s.v. "promissory oath") simply teaches that every violation of a promissory oath is a mortal sin; this doctrine he mitigates somewhat in his Commentary on 2, 2, q. 89, a. 7.

⁵⁶⁷ De iust. l. 2, c. 42, dub. 5.

⁵⁶⁸ In 2, 2, disp. 6, q. 7, punct. 3, concl. 3.

⁵⁶⁹ In Decal. l. 5, diss. 2, c. 1.

⁵⁷⁰ S. theol. 2, 2, q. 110, a. 3 ad 5.

⁵⁷¹ S. theol. P. 2, tit. 10, c. 4, § 1.

⁵⁷² Theol. mor. l. 3, n. 173.

⁵⁷³ De iure et iust. l. 8, q. 1, a. 7, dub. 1.

⁵⁷⁴ In 2, 2, q. 88, disp. 29, a. 8.

⁵⁷⁵ Summa Summ., s.v. "Iuramentum" 4, q. 1.

⁵⁷⁶ Cf. Göpfert, Moraltheol. I, 357.

451. Conditions required for inducing an obligation.

The due conditions of a promissory oath for inducing its obligation are similar to the conditions indicated above in n. 392ff. for the validity of a vow; therefore, they are required both on the part of the matter and on the part of the person swearing.

On the part of the matter it is required that the thing promised by oath be: a) possible; b) good and lawful.

Hence an oath is invalid a) concerning an impossible thing, because no one can bind himself to an impossible thing; b) concerning a dishonorable thing, because otherwise a manifest conflict of duties would arise: for by natural law a man is bound to avoid every dishonorable and unlawful act, but by the oath he would have to perform the same act. Hence Rule of Law 58 in VI° says: "An oath taken against good morals is not obligatory."⁵⁷⁷ c) Concerning an entirely vain and useless thing, because every true oath ought to intend the worship of God. But God cannot be worshiped by entirely vain and useless things.⁵⁷⁸ Because of inept matter, the oaths of Freemasons, an oath concerning telling a lie, and an oath concerning taking revenge are invalid, for example. The oaths also of parents or masters by which they threaten that they will punish, beat, or cast out their children or servants in such a determinate way are almost always invalid, both because a true intention of swearing is absent and because it is very doubtful whether such an oath concerns apt and useful matter.

⁵⁷⁷ Cf. also c. 1, II 11 in VI°.

⁵⁷⁸ Cf. what was said above in n. 400 concerning the matter of a vow.

452. Scholion. On the obligation of an oath of fidelity. A special difficulty can arise concerning the so-called oath of fidelity,⁵⁷⁹ i.e., an oath of obedience and fidelity which officials, soldiers, and indeed, in certain regions, bishops must take to princes or to the public authority. This oath of fidelity (a legitimate government being supposed) is lawful of itself. If priests or bishops should at any time be compelled to take an oath of this kind, first the concordats in force between the Holy See and the civil power are to be attended to. Then the one swearing neither can nor ought from the virtue of religion to bind himself to observe each and every law, even the unjust laws, of that region, but must always understand the clause: the laws of God and of the Church being preserved. For the rest, the meaning of the oath taken is customarily no other than that the priest or bishop wills to undertake nothing against legitimate civil authority and that he intends faithfully to exercise the office entrusted to him. Officials and soldiers are not bound by force of an oath of fidelity to unlawful things, since no one can bind himself before God to an unlawful thing. A soldier who, after making an oath of fidelity, deserts the army certainly sins, unless, however, a) he was unjustly compelled to military service; b) because of military service he is placed in the most urgent danger of eternal salvation. In our times either case can scarcely ever occur if it concerns laymen destined for military service. For dangers to eternal salvation existing in the army can be guarded against by means other than desertion, e.g., by avoiding evil companions or denouncing them to legitimate authority. A soldier who has already deserted the army in an unlawful manner ought not be compelled by a confessor to return to the army, both a) because the most bitter penalties will be inflicted upon him and therefore the fulfillment of the oath has become morally impossible, b) because so grave a loss is not caused to the commonwealth by the desertion of one or another soldier, and c) because the admonition of the confessor would probably be ineffective.⁵⁸⁰

⁵⁷⁹ Diensteid, Amtseid, Fahneneid [oath of service, oath of office, military oath].

⁵⁸⁰ Cf. above I, n. 301.

453. On the part of the person swearing there are required: a) an intention of swearing; b) sufficient deliberation; c) liberty; d) absence of substantial error.

a) Concerning the intention necessary for the validity of an oath, something has already been said above in n. 441.

b) That deliberation is considered sufficient which is required for a perfectly human act or even for entering an onerous contract. Because of a defect of sufficient deliberation, the oaths of the intoxicated, the demented, the furious, and others lacking the perfect use of reason are invalid.

c) Liberty is required for the validity of an oath, so that an oath extorted by irresistible force or physical violence is altogether invalid.

It was greatly disputed whether an oath made under the influence of grave fear is valid. All indeed agreed that oaths made under the influence of grave fear unjustly inflicted can be rescinded by legitimate authority; likewise, all conceded that one who made an oath from grave fear unjustly inflicted can recover in court the things which he paid because of such an oath. Finally, positive law so establishing, certain oaths made from grave fear are by that fact invalid, e.g., concerning entering betrothals and marriages,⁵⁸¹ and concerning making religious profession.⁵⁸² But apart from these cases, the more common and more probable opinion taught that oaths made from grave fear are valid. Thus teach St. Thomas,⁵⁸³ St. Alphonsus,⁵⁸⁴ Dominic Soto,⁵⁸⁵ Billuart,⁵⁸⁶ Suarez,⁵⁸⁷ Lugo,⁵⁸⁸ Göpfert,⁵⁸⁹ and others. This opinion has now been defined in Code of Canon Law, c. 1317, § 2, which establishes: "An oath extorted by force or grave fear is valid, but can be released by an ecclesiastical superior." On this matter the Angelic Doctor already briefly handed down the whole doctrine:⁵⁹⁰ "In an oath which someone makes under compulsion there is a twofold obligation: one indeed by which he is bound to the man to whom he promises something; and such an obligation is removed by compulsion, because the one who inflicted the force deserves this, that the promise not be kept to him. But the other is the obligation by which one is bound to God to fulfill that which he promised by His name; and such an obligation is not removed in the forum of conscience, because he ought rather to sustain temporal loss than to violate the oath."

"He can, however, recover in court what he paid; or denounce the matter to the prelate, notwithstanding that he swore the contrary, because such an oath would tend to a worse outcome, for it would be against public justice."

d) Substantial error invalidates an oath in the same way that it invalidates a vow made with such an error; accidental error, however, invalidates neither an oath nor a vow. Cf. what was said above in n. 396 concerning vows made with error.

⁵⁸¹ Cf. below in the tract on marriage III, n. 719.

⁵⁸² C. 1, X 1, 40; Council of Trent, sess. 25, c. 19 de regularibus.

⁵⁸³ S. theol. 2, 2, q. 89, a. 7 ad 3, and q. 98, a. 3 ad 1. Cf. above n. 266.

⁵⁸⁴ Theol. mor. l. 3, n. 174.

⁵⁸⁵ De iure et iust. l. 8, q. 1, a. 7.

⁵⁸⁶ De relig. diss. 5, a. 6, § 3.

⁵⁸⁷ De relig. tr. 5, l. 2, c. 10, n. 4.

⁵⁸⁸ De iust. disp. 22, n. 194.

⁵⁸⁹ Der Eid, 288.

⁵⁹⁰ S. theol. 2, 2, q. 89, a. 3 ad 3.

454. 2. The interpretation of an oath is to be made according to the following three rules:

First rule. A promissory oath is of strict interpretation.⁵⁹¹ The words of an oath are indeed to be understood in their obvious sense; but when a prudent doubt arises, as small an obligation as possible is to be imposed upon the one swearing. The reason is that the one swearing is not considered to have willed to bind himself beyond the strict sense of the words. Nor is it an objection that an oath is to be interpreted in favor of religion, because the more benignly an oath is interpreted, the more rarely it is violated, the more securely it is observed, and the more sacredly religion is preserved.

Second rule. In every promissory oath, however absolutely pronounced, the following conditions and limitations are understood, whether from the nature of the matter, from a provision of positive law, or from custom:

a) "If I shall be able physically and morally, I shall observe the oath." For no one of sound mind wills to bind himself to the impossible.

b) "The right of the superior being preserved." For a subject cannot diminish the right of the superior; but the latter, for a just cause, can release or dispense an oath.

c) "Unless the other remits my obligation, yielding his right."⁵⁹² For the principal obligation of an oath arises from the promise made. But if the other remits the obligation of the promise, by that very fact he also remits the obligation of the oath. Hence sworn betrothals can be dissolved by free mutual consent.

d) "If circumstances have not been notably changed."⁵⁹³ For a notable change supervening produces, as it were, a new object to which the intention of the one swearing is not presumed to have extended; e.g., if a young man promised a girl marriage under oath, nevertheless he is no longer bound to execute the sworn promise if the girl has committed fornication or has fallen into a grave and incurable disease. For the rest, the things which we said above in n. 410 concerning the cessation of a vow because of a notable change of matter apply here.

e) "If the other has stood by his promises." For let faith be broken with one who breaks faith; or, as Rule of Law 75 in VI° says: "In vain does anyone ask that faith be kept with himself by one to whom he refuses to keep the faith pledged by himself."

Third rule. A promissory oath generally follows the nature and conditions of the act to which it is added; therefore, if such an act tends directly to the harm of others or to the prejudice of the common good or of eternal salvation, it obtains no firmness therefrom.⁵⁹⁴ The reason is that an oath is assumed for confirming an act by adding an obligation of religion, and therefore it is something accessory to the principal act. But "it is fitting that the accessory follow the nature of the principal," as Rule of Law 42 in VI° says. From this rule it is deduced that one who swore that he would observe the decrees and statutes of some congregation, chapter, or University is not bound to observe all these otherwise than they are observed by the other good members of the same society. Hence those things which are commonly neglected can also be neglected by him; those things which of themselves bind under light sin are not to be observed otherwise because of the oath made; those things which bind from a certain fittingness alone also do not bind more from the oath.⁵⁹⁵

⁵⁹¹ Code of Canon Law, c. 1321.

⁵⁹² Ib., c. 1319, n. 1.

⁵⁹³ Ib., n. 2.

⁵⁹⁴ Code of Canon Law, c. 1318.

⁵⁹⁵ Cf. St. Alphonsus, Theol. mor. l. 3, n. 181. Even an oath concerning keeping a secret is understood according to the gravity of the matter, so that the violation of this secret in grave matter is a grave sin; in light matter, a light sin; in matter of no importance, no sin. Cf. Billuart, l.c.

455. 3. The cessation of the obligation of a promissory oath can be produced either by extrinsic causes or by intrinsic causes. From intrinsic causes the obligation of an oath ceases in almost the same way as a vow, namely, through a substantial change of matter (as if it has become unlawful or impossible); through the cessation of the essential end (as if someone promised alms by oath to poor Peter, who has now suddenly become rich or has died); through the failure of the condition under which the oath was made.⁵⁹⁶

The extrinsic causes which produce the cessation of an oath are:

a) the remission by the other person in whose favor the promise confirmed by oath was made, as is clear from the second rule, letter c), cited above.

b) invalidation, dispensation, commutation. Before the Code of Canon Law was published, certain controversies existed concerning this matter. But now c. 1320 simply establishes: "Those who can invalidate, dispense, or commute a vow have the same power and in the same manner concerning a promissory oath; but if the dispensation of an oath tends to the prejudice of others who refuse to remit the obligation, the Apostolic See alone can dispense the oath because of the necessity or utility of the Church." Therefore, e.g., betrothals confirmed by a promissory oath can be dispensed by the Holy See alone, unless, however, both betrothed parties consent to the dissolution of the betrothal. Apart from this oath in favor of a third person, no other seems to be reserved to the Holy See.⁵⁹⁷

c) Release,⁵⁹⁸ which differs from dispensation in this, that dispensation is customarily granted in favor of the person swearing, but release from an oath is commonly imposed because of grave reasons on the part of the one in whose favor the oath was pronounced. This release is similar to the invalidation of an oath, but since it tends to the prejudice of others, it is not exercised except by the Supreme Pontiff,⁵⁹⁹ and indeed:

a) for preventing harm to the common good. For a private good ought to yield to the common good. Therefore the Pope releases even sworn betrothals for a grave cause if, e.g., otherwise an unbelieving betrothed man would contract a merely civil marriage or live in concubinage. Certainly the betrothed woman thus abandoned can suffer great harm from such a release, but the Church cannot compel the unbelieving betrothed man to the promised nuptials, and on the other hand, for the sake of the common good, she must avoid merely civil marriages and concubinages as far as possible. b) As punishment for a crime committed. Therefore in ancient times the Supreme Pontiffs more than once released the citizens' oath of fidelity because of the crimes of an excommunicated prince. c) For repairing an injury which was inflicted upon the one swearing, if, namely, he was induced to the oath by fear or fraud.⁶⁰⁰

⁵⁹⁶ Cf. what was said above in n. 410 concerning the cessation of a vow, and Code of Canon Law, c. 1319, nn. 2 and 3.

⁵⁹⁷ Cf. St. Alphonsus, Theol. mor. l. 3, n. 259.

⁵⁹⁸ Eideslösung, délier d'un serment [release from an oath].

⁵⁹⁹ Cf. S. theol. 2, 2, q. 89, a. 9 ad 3; Code of Canon Law, c. 1320.

⁶⁰⁰ S. theol., l.c., a. 7 ad 3.

371. Principles. - I. Every promissory oath concerning a licit and honorable thing, besides the obligation of justice or fidelity which arises from a simple promise, also induces an obligation of Religion. The reason is that the promise already obligates of itself, and it is confirmed and strengthened by divine testimony invoked. - But an oath concerning an illicit or wholly useless thing does not obligate at all, because an oath, as an act of Religion, cannot be a bond of iniquity or of an idle thing.

II. The obligation of an oath is to be interpreted strictly, and follows the nature of the act or contract to which it is added, and all its conditions. The reason for the first is that the one swearing is judged to have willed to obligate himself as little as he could; but the reason for the other is that the oath does not change the nature of the act, but adds to it only the obligation of Religion, and hence ought to have the same conditions and limitations.

III. The obligation of an oath is moreover to be interpreted according to the tacit conditions included or understood in it, which are: 1° if I shall be able without grave damage; 2° if the matter shall not have been notably changed; 3° if the rights or will of the Superior do not stand in the way; 4° if the other shall have preserved reciprocal faith; 5° unless the other cedes from his right.¹

372. Questions. - Quaer. 1° Is smallness of matter given in the transgression of a promissory oath?

Resp. The FIRST OPINION denies, because not only a simple promise is violated, but a sworn promise. Therefore in any matter whatsoever grave injury is inflicted on God, whose testimony has been invoked in vain by the one swearing. - Bonacina, Lessius, Toletus.

The SECOND OPINION affirms, because in a promissory oath God is not properly brought forward as witness of the future execution of the thing promised, but only of the actual promise, or of the true intention of executing the promise. - Suarez, Navarrus, Laymann, etc. - St. Alphonsus in the Work² says each opinion is probable; but in the Homo apostolicus³ he adheres more to the second opinion.

Quaer. 2° Does a promissory oath emitted by error or deceit obligate?

Resp. Negatively, if the error or deceit concerns the substance of the thing; but otherwise if it affects only its accidental adjuncts; because a simple contract would be invalid in the former case, but not in the latter. St. Alphonsus.⁴ Yet the same St. Alphonsus⁵ notes that the opposite opinion is probable when the error or deceit concerns those circumstances which, although accidental, if they had been known from the beginning, would have deterred from the oath and promise.

373. • Quaer. 3° Does a promissory oath extorted by grave and unjust fear obligate?

Resp. It is disputed. The more common OPINION, and in St. Alphonsus⁶ by far the more probable, affirms, because an oath, acceding to a contract not invalid of itself, must be preserved from Religion as often as it can be preserved without sin. But the one who has suffered fear can either rescind the contract by force of laws, or seek relaxation of the oath, that he may be excused from the obligation of paying; but if he has already paid, he can demand back in court what he gave, or compensate himself secretly.⁷ Cf. n. 867.

Quaer. 4° How does the obligation of an oath cease?

Resp. 1° It ceases intrinsically, as a law does, by cessation of the motive cause (n. 165).

Resp. 2° It ceases extrinsically by irritation, commutation, and dispensation, as a vow does, concerning which we shall speak in the following chapter. It also ceases by relaxation or remission of the obligation made by him in whose favor the sworn promise was emitted, because anyone can yield from his own right.

374. You will resolve. - 1° He who swore an evil thing is never obligated by the oath; indeed he sins doubly if he fulfills the oath, namely against Religion and against the virtue to which the matter of the oath is opposed.¹

2° He who confirmed a prodigal promise by swearing is not obligated by the oath, because that promise is at least lightly evil. - Thus Suarez, the Salmanticenses, and others commonly with St. Alphonsus, who admits this as more probable.²

3° He who swore that he promised marriage to a rich, healthy, virgin girl of good reputation is not obligated if she falls into poverty, infirmity, infamy, or fornication, because then the simple promise does not obligate.³

4° He does not sin against the oath who, for the sake of civility, swore that he would not sit, drink, enter the house, etc. before another, if compelled by the other he sits, drinks, or enters first; because generally an oath of this sort is null from defect of intention of swearing; or, if it is valid, it is relaxed by the other.⁴

5° He does not sin who reveals a sworn secret when the law itself of the secret ceases to obligate; because an oath, as we said, follows the nature of the act to which it is joined.

6° Parents rarely sin when not fulfilling an oath of punishing children, because generally the oath concerns a useless thing, or rather disordered vengeance; added to this is that the delinquents either are already corrected, or at least have promised amendment.⁵

7° Generally merchants also do not seem to be bound by an oath not to sell for less, or not to buy for more; either because oaths of this kind are, for the most part, concerning a useless thing, or because those men do not have the mind of swearing, or certainly because in the oath there is the tacit condition, unless matters seem to go better otherwise. - Thus more commonly.

8° The oath by which alumni of the Sacred Congregation de Propaganda Fide bind themselves (see p. LXXIII, note 2), and those who here or elsewhere are ordained to the title of the American Mission, that they will not enter any Religion or Congregation without permission of the Holy See, is valid, since it is in favor of a third party.¹ Besides, the condition added, without permission of the Holy See, causes no one to be prohibited absolutely from entering Religion. (x) p. 473.

But it is violated: 1) if someone, when the Bishop commands, should refuse to receive the Orders of diaconate or priesthood; 2) if he should refuse to betake himself to that place of the diocese in which the Bishop shall have judged that he ought to labor unto the salvation of souls; 3) if through his whole life he is unwilling to remain in the same diocese, or employs crafts and deceits to withdraw himself from the authority of the Bishop, or by this manner of acting introduces for the Bishop the necessity of dismissing him; 4) if he enters a religious Order without due permission.

Yet they are not to be judged to sin: a) subdeacons who, by the counsel of a confessor or agitated by scruples, would be unwilling to be promoted to the diaconate, or deacons who for the same reason would be unwilling to be promoted to the priesthood; b) those who for a grave cause seek leave of passing to another diocese; c) those who, knowing themselves not suitable, either from defect of knowledge, or because of infirmity of soul, decline the burden of laboring in the vineyard of the Lord; yet they ought not to trust their own judgment against the mind of the Bishop and confessor.²

9° Oaths imposed for securing observance of odious laws, or laws which are of strict interpretation, as, for example, those which pertain to customs duties and other burdens, are to be reduced to the narrowest limits which the words allow.³ - Resolve the same if those laws were unjust or are deservedly presumed unjust.⁴

For one or the other of these reasons, and often for both, those seem to be excused from perjury who see to it that a double document (invoice) of the goods which they have bought, for example from Europe, be permitted to themselves: one in which the lesser price of the goods is described, another in which the greater is noted; and, with only the former exhibited, swear that they bought at the price which is reported in this former one, provided nevertheless that the formula of the oath is not of such a kind as to preclude the possibility of broad mental restriction.

It happens besides that a merchant who paid the duties defined by law could scarcely gain anything by trading for the support of himself and his own, and this for the reason that either the duty is really excessive, or defrauding the duty as to this kind of merchandise has become common, from which it has come about that merchandise of this sort, if the whole duty is paid, cannot be sold at the price at which, because of common defrauding, it is generally sold. Such a merchant also seems to be excused, if he swears with words used in the strictest sense which they allow;¹ for in these cases the tax law has become unjust, either because it imposes an excessive burden, or because practically, namely from the fact that it is preserved by almost no one, it would burden too much the merchants who preserved it.

Nevertheless officials sin most gravely who, against the oath by which they have bound themselves, accept gifts so that they allow goods to be brought in immune from duty or under a duty lower than that which has justly been established.

S. Th. II-II, q. 89, a. 7-9.

755. The intrinsic effect of a promissory oath is the obligation of executing the thing sworn from the virtue of religion. - It is certain, both from Scripture (Num. XXX, 3; Mt. V, 33), and from reason, because he who does not fulfill a promise confirmed in His name inflicts injury upon the authority of God (can. 1317, § 1).

The obligation is grave from its genus, yet probably admits lightness of matter, just as a vow does.

It is proved: 1. directly. Because the obligation of a vow is graver than the obligation of an oath as promissory.¹ For the former is caused from the fidelity which we owe to God Himself, so that we pay Him what was promised; the latter is caused from reverence toward God, from which we are bound to verify that which through His name we promised before Him. But the obligation of fidelity regards God more directly than the obligation of reverence, for infidelity contains irreverence, not conversely, and infidelity toward a lord is the greatest irreverence. Therefore we are more strictly bound to do that which we promised to God Himself than that which we promised with God only as witness (a. 8). Whence if the obligation of a vow admits lightness of matter, a fortiori the obligation of a promissory oath does.

¹ We say: as promissory. For the obligation of an oath as assertory is greater: there it is a negative precept not to swear falsely, which is directly contrary to God; here it is an affirmative precept of fulfilling a sworn promise. But a negative precept obliges more than an affirmative.

2. indirectly. Because the violation of a promissory oath is not proved to be perjury strictly so called, as the adversaries² contend, saying: He who does not fulfill an oath makes it be false and lying, because he makes God witness of a lie. For he who does not fulfill what he sincerely promised does not make a lie; because he does not say or do against his mind, but only changes his mind, inconstant and unfaithful, as St. Thomas himself explains (II-II, q. 110, a. 3, ad 5). Therefore he who does not fulfill what he sincerely swore does not make God witness of a lie, provided he had the intention of fulfilling the oath; but he only acts inconstantly or unfaithfully in a thing promised under divine authority, and thus contracts irreverence toward God, which is a grave or light sin according to the gravity or lightness of his inconstancy or infidelity.

² For example, Cajetan, Toledo, Valentia, Lessius, Gabriel, Bonacina, etc. On the contrary, St. Antoninus, Sylvester, Soto, Suarez, Laymann, Navarrus, Sylvius, Azor, the Salmanticenses, Billuart, and almost all moderns.

In other words, violation of an oath as promissory is not a sin which directly opposes a divine attribute, and therefore it is not necessarily and always mortal.

Nevertheless it does not follow that someone can oblige himself by oath under light obligation in grave matter, as for a vow. For the disparity is that to promise is nothing other than to will to oblige oneself, whence the whole obligation of a promise immediately depends upon the will of the agent, who can promise or oblige himself more or less. But an oath is not directly for obliging but for the confirmation of truth by divine testimony, from which confirmation obligation naturally follows, because of the reverence of God; whence this obligation of an oath does not depend only and immediately upon the will of the one swearing, but upon the law of reverence owed to God, because it is a consequence of the testimony invoked. For someone cannot swear more or less, or invoke God as witness more or less, but he either invokes or does not invoke, and once He is invoked, God is patron of the obligation and urges fulfillment from the law of reverence owed to Him, which is greater or less not indeed according to the intention of the one swearing, but according to the gravity of the promise or of the promised matter sworn.

756. The conditions required for the validity of a promissory oath, both on the part of the act and on the part of the matter, are almost the same as for a vow.

Yet there are two exceptions:

1. An oath made in favor of a third party need not be made concerning a better good, but it suffices that it be concerning a good useful to one's neighbor. The direct end of a vow is the greater worship and honor of God; but the direct end of an oath is the confirmation of truth, which can also be had in a lesser good.

2. Even grave and unjust fear does not invalidate an extorted oath, as is now altogether certain from canon 1317, § 2, because although it renders the act involuntary in a certain respect, nevertheless it does not simply remove the voluntary. Whence an oath remains a human act and consequently is capable of inducing obligation; which nevertheless can, in the name of God, be relaxed by an ecclesiastical superior.

Nor should you say that God does not accept an oath extorted by injury, because an oath is not made in favor of God nor must it be accepted by Him, but is a simple appeal to His testimony; that God as patron gives authority to the promise is only a consequence of the invocation. Yet in the case the one swearing can use a restriction: I will give insofar as you have a right; but if he did not do this but truly invoked, he is bound to pay the promise, yet he can immediately seek back in judgment what he paid (a. 7, ad 3).

If a condition required for the validity of an oath is lacking, sin is committed, grave or light, in the same way as was said concerning a vow (n. 721). But he who swears fictitiously or merely externally is not obliged by force of the oath from religion, but can sometimes be held because of scandal or harm inflicted.

757. The obligation of a promissory oath must be fulfilled and ceases in the same way as was said concerning the fulfillment of a vow (n. 727) or its release from obligation (n. 732). Yet the obligation of an oath ceases not only by all the things by which the obligation of a vow ceases, but also by the renunciation of the third party or by condonation made by him in whose favor it principally redounds (a. 7, ad 2 and a. 9; can. 1319).

But three things should be noted: 1. that he who can irritate, dispense, or commute a vow can by that very fact do this concerning a promissory oath (can. 1320); 2. but if the dispensation of an oath tends to the prejudice of others who refuse to remit the obligation, the Apostolic See alone can dispense, and only because of necessity or utility of the Church or the common good (ibid.); 3. probably no oaths are reserved, even if they confirm reserved vows.

758. The obligation of a promissory oath is to be interpreted strictly, because the one swearing is judged to have wished to oblige himself as little as he could. Thus especially canon 1321, conformably to St. Thomas, a. 7, ad 4.

Hence: a) An oath per se, and unless the one swearing intended otherwise, follows the nature of the act to which it is joined: the accessory follows the principal; therefore if it is added to a vow, promise, or contract, its obligation will have the same extension, the same limits, and the same expressed or tacit conditions (can. 1318, § 1). Thus, for example, an oath of keeping a secret, residence, a contract such as betrothal, the statutes of a college, fidelity toward a regime, per se does not oblige beyond what is demanded by the matter of the secret, or the law of residence, or the nature of the contract, for example, of betrothal, or the custom had concerning the statutes of a college not to be published but already published, or the fidelity of a regime insofar as it is not opposed to a superior divine and ecclesiastical right.

b) "If an oath is added to an act directly tending to the harm of another or to the prejudice of the public good or of eternal salvation, the act obtains no firmness from it" (can. 1318, § 2).

c) Although an oath does not have the force of validating and confirming invalid or rescindable contracts, nevertheless, if the contract is invalid, it can induce an obligation of religion, if it is emitted absolutely and independently of the obligation of the contract, so that the one swearing is prohibited by religion from seeking the annulment of the contract, and, with the contract irritated, the obligation of religion remains until there is dispensation in it. Then, namely, there is a mere purpose confirmed by oath and a promissory oath broadly so called or standing of itself.

d) Oaths very often used: of not selling for less or not buying for more, of not granting or accepting a favor, of chastising a subject, etc., generally do not oblige, because the intention of swearing is lacking, or the matter is vain and useless, or finally the condition understood is lacking (for example, if the matter is not otherwise more opportune), or the state of things is sufficiently changed.

I Say 1st. Every promissory oath concerning a licit and honorable thing, besides the obligation of fidelity or even of justice, also induces an obligation of religion; but it in no way obliges if it is concerning an illicit or plainly useless thing. The reason of the first is that, when a new bond imposed by a different virtue has been added, a new obligation ought to arise. But the reason of the second is that an oath, as an act of religion, cannot be a bond of iniquity or of an idle thing; nor does that oath afterward revive, even if the thing ceases to be idle or illicit, for according to the rule of law 18, in 6: "What does not subsist in law from the beginning is not made firm by the passage of time." - Cf. Baller., note (b), p. 307.

§ 1. He who freely swears that he will do something is held by a peculiar obligation of religion to fulfill what he has confirmed by oath (Can. 1317).

I Say 2nd. The obligation of an oath is to be interpreted strictly, and it follows the nature of the act or contract to which it is added, and all its conditions. The reason of the first is that one swearing is judged to have wished to oblige himself as little as he could; but the reason of the second is that an oath does not change the nature of the act, but superadds to it only the obligation of religion, and therefore ought to have the same conditions. - Besides, the obligation of an oath is to be interpreted according to the tacit conditions included or understood in it, which are: 1st, if I can without grave damage; 2nd, if the thing shall not have been notably changed; 3rd, if the rights or will of a superior do not stand in the way; 4th, if the other has kept reciprocal faith; 5th, unless the other yields concerning his right. - Cf. St. Alphonsus, n. 180.

§ 3. An oath taken neither by force nor by fraud, by which someone renounces a private good or favor granted to him by law, must be observed whenever it does not incline to the detriment of eternal salvation (Can. 1317).

I Say 3rd. § 1. A promissory oath follows the nature and conditions of the act to which it is added.

§ 2. If an oath is added to an act directly tending to the damage of others or to the prejudice of the public good or of eternal salvation, the act obtains no firmness from it (Can. 1318).

I Say 4th. An oath is to be interpreted strictly according to the law and according to the intention of the one swearing, or, if he acts by fraud, according to the intention of him to whom it is sworn (Can. 1321).

Question 1. Is there smallness of matter in the transgression of a promissory oath?

Response. Affirmatively, probably. For in a promissory oath two things are to be distinguished, namely the actual truth of the promise, or of the intention of carrying out the promise, and the future execution itself of the promise. Now God is indeed invoked as witness of the truth of the intention; but as regards the execution itself, he is brought forward only as guarantor, or as a person furnishing authority to the obligation which arises from the promise made before him and otherwise valid, just as a prince by his authority renders pacts contracted before him firmer. But since we now suppose that the intention of fulfilling the sworn promise was sincere, the malice of this transgression is to be measured not from injury toward the truthfulness of God, but only from irreverence inflicted upon his authority. But since this is not direct and formal, nor greater - indeed according to St. Thomas less - than that which is had in the transgression of a vow, it follows that smallness of matter can exist in the transgression of a promissory oath. - Cf. St. Alphonsus, n. 173; and Hom. Ap., n. 13. Baller., note (a), p. 308.

Question 2. Does a promissory oath emitted through error or fraud oblige?

Response. Negatively, if the error or fraud concerns the substance of the thing, because then a simple contract would be invalid; but if it affects only accidental circumstances, one must subdistinguish: it indeed obliges in onerous contracts, but not in gratuitous ones, at least probably, if the circumstances, although accidental, are nevertheless such that if they had been foreseen from the beginning, they would have deterred one from both the promise and the oath. - Cf. St. Alphonsus, n. 175. - Baller., note (b), p. 308.

Question 3. Does a promissory oath extorted by grave and unjust fear oblige?

Response. § 2. An oath extorted by force or grave fear is valid, but can be relaxed by an ecclesiastical Superior (Can. 1317).

Question 4. In what way does the obligation of an oath cease?

Response. The obligation induced by a promissory oath ceases:

1st. If it is remitted by him for whose advantage the oath had been emitted;

2nd. If the sworn thing is changed substantially, or, the circumstances having been changed, becomes either evil or altogether indifferent, or finally impedes a greater good;

3rd. If the final cause or condition under which perhaps the oath was given is lacking;

4th. By irritation, dispensation, commutation, according to the norm of can. 1320 (Can. 1319).

Question 5. Can he who has a delegated faculty of dispensing in vows also dispense in oaths?

Response. Affirmatively. Those who can irritate, dispense, or commute a vow have the same power and by the same reason concerning a promissory oath; but if the dispensation of the oath inclines to the prejudice of others who refuse to remit the obligation, only the Apostolic See can dispense the oath on account of necessity or the utility of the Church (Can. 1320).

Those matters have thus far been discussed which concern the oath in common, and especially the assertory oath. It remains now that I take up a discourse concerning the promissory oath. This indeed has its own peculiar difficulties, since, beyond the truth of a present assertion, it carries with it a promise to be fulfilled in the future. In this disputation, then, I shall first examine those difficulties which pertain to truth, judgment, and justice; then I shall set forth the extent of the obligation which this oath induces.

I. Hugo Grotius (Bk. II, On the Law of War and Peace, ch. 13, §21) denies that a promissory oath is lawful, on the grounds that the outcome of the promised matter is uncertain. And against these oaths he adduces the text of the Gospel: "Swear not at all." But Grotius, an author otherwise weighty among the heterodox, errs, and his own error even the heretics themselves have refuted, in their notes. Wherefore, this error set aside, the opinion of the Catholics is to be explained. The concordant opinion of the Doctors, then, is that all three conditions — namely, truth, judgment, and justice — are necessary in a promissory oath, no less than in an assertory one. For the aforesaid conditions ought to accompany the oath, taken absolutely, and consequently any particular oath whatsoever. Concerning the judgment which it is necessary to examine for the necessity of swearing, nothing occurs to be said beyond what has been said in the preceding dissertation. For no oath can lawfully be made without a reasonable necessity. This necessity is now greater, now lesser, according to the diversity of the matter which is sworn. Having, then, made a general examination of this condition, which brings no new difficulty, we undertake to elucidate the truth which is necessary in a promissory oath, and which is subject to its own peculiar difficulties.

II. Question I. Is the defect of truth concerning the present, in a promissory oath, always a mortal sin? Response: It has already been said that a promissory oath includes a twofold truth: one, concerning the present... , which consists in this: that the swearer have a sincere mind of fulfilling what he promises; the other, of the future, which consists in the future execution of the promised thing. It is answered, then, to the question, that all defects of present truth in a promissory oath are always a mortal sin. The reason is evident: since a promissory oath, by reason of present truth, agrees with the assertory, as has been indicated above. Now the attestation of falsity concerning the present is always a mortal sin, even in the lightest matter; therefore also in a promissory oath, no less than in an assertory one. For in both, God is invoked as witness of a falsity, which betrays a most grave injury to him. Whether, then, a small matter, or a great one, whether honorable or unlawful, is promised, without truth concerning the present — that is, without the intention of fulfilling such a promise confirmed by oath — it will always be a mortal sin.

III. Question II. Is a defect of the second truth to be judged grave, or is one who does not fulfill a promised matter confirmed by oath, in grave matter, guilty of mortal sin? Response: All respond affirmatively — since the violation of an oath in a grave matter gravely holds God in contempt, and consequently is a mortal sin — just as it must, by a stronger right, be said of the violation of a vow in a grave matter. Nor is there any difficulty among theologians about this.

IV. Question III. Does one who does not fulfill a promised matter confirmed by oath in light matter sin mortally? Response: Theologians dispute on both sides. I will first premise what is certain among all; then I will set forth what seems to me more probable. First of all, then, all confess that one who confirms a verbal promise by oath, without the intention of promising, sins mortally — since he is thus already a perjurer, as has been said. All equally affirm that one who has the intention of promising, but does not have the intention of fulfilling, sins mortally, for the same reason: because in both cases he lies, and perjures himself. For, when someone swears that he will assume the burden of another's obligation, and in fact, from a defect of intention, does not assume it, he lies — just as one who swears that he will do something swears that he has the resolve of doing it. If, then, he does not have this resolve, he lies, and is a perjurer. All equally agree that a twofold truth is given in a promissory oath — one, concerning the present, which, as we have said, consists in the intention of promising and of fulfilling; the other, concerning the future, which consists in the execution of the promised thing. Finally, all concede that the defect of either truth in the oath is, by its own kind, and absolutely, a mortal sin.

In this, however, turns the whole controversy: namely, whether there is a smallness of matter in this second truth of the promissory oath. And a threefold opinion is repeated on this matter. The first, extreme opinion, which affirms it; another, which denies it; a third, middle opinion, which uses a distinction. If the promised matter is the whole and entire matter of the oath, though it be light — for example, if you swore, or vowed, that you would give a poor person one small coin — then the omission of its execution is a mortal sin. If, however, the matter omitted is partial — for example, if you swore that you would give ten pieces of silver, and you give only eight — then the omission is only a venial sin. But authors of both extreme opinions commonly reject this third, middle opinion, as useless. For, granting that the defect of truth in the whole matter is a lie, the same occurs in the defect of a part of the matter. For to bring God forward as a witness of a lie, in whatever way this occurs, is always a mortal sin. Setting aside, then, this middle opinion, it is brought under examination which of the two extreme opinions is more probable.

V. I say: one who does not fulfill a promised matter confirmed by oath, even though the matter be light, nonetheless commits perjury, and sins mortally. So that you may perceive the sense of this opinion of ours more clearly, I would have you note that we do not now speak of those oaths by which mothers swear to their children an apple which they do not afterward give; nor of those by which men swear that they will not go forward, or deny that they will do something, out of modesty, to honor their companions, though they nonetheless go forward. Of these, or similar oaths, I say, we are by no means speaking. Indeed, with Comitoli (Bk. II, q. 4), we confess that it would be too harsh to condemn such mothers, or well-born men, of mortal guilt — since such expressions, or oaths, are not true oaths, from a defect of sufficient deliberation; or they receive a true interpretation, which we have given elsewhere. One ought, nonetheless, to abstain from oaths of this kind. We speak, then, of a serious and deliberate oath, by which men pledge something under oath.

We choose this opinion as more probable, since, in express words, St. Augustine, St. Thomas, St. Raymond, and the weightiest theologians to be cited below teach it, as I judge. St. Augustine (Epistle 22, or 224 in some editions) has this: "Whoever deceives the expectation of those to whom he swears, cannot fail to be a perjurer." St. Thomas more clearly (II-II, q. 89, art. 7, in the body): "Just as an assertory oath, which is about the past or the present, ought to have truth, so too an oath about things to be done by us in the future ought to have truth. And therefore each oath has a certain obligation, though in different ways: for in an oath which is about the past or the present, the obligation is not with respect to the thing which already was, or is, but with respect to the very act of swearing — namely, that one swear that which is now, or was, already true. But in an oath which is rendered concerning things to be done by us, the obligation, on the contrary, falls upon the thing which someone has confirmed by oath. For one is bound to make true that which he has sworn; otherwise the truth of the oath is lacking. This is so well established, so evident, is St. Thomas's mind, that it can be evaded by no circumlocution." — as will already appear more clearly. St. Raymond (Bk. I, Summa, tit. on the oath, on perjury, p. 51, col. 1) has this: "If, when he swore, he either believed that he could, but foolishly, or he believed that he could not solve it, and had probable cause for believing, then in both cases he perjured himself, as regards his ability, in either case; not, however, as regards his will, since he had the will in both cases: because in the first case he lacked truth in conscience, and in the second, judgment. If, however, he could not pay at the term, he does not perjure himself for this cause. Much more is he excused, if he sent it at the due time, but the money was lost by chance in transit, as is gathered from the chapter "Querela," Extra, on the oath, from the canon "Si nulla," cause 23, q. 8, and canon "Sicut," dist. 1, on consecration. If, however, once the term has elapsed, he could pay, and does not pay, he would be a PERJURER. For the lapse of the term does not dissolve the obligation of the oath, as is gathered from the chapter "Cum dilecti," Extra, on deceit and contumacy."

The Catechism of Trent teaches this same opinion (Part III, on the 2nd precept, n. 13), where it proposes this question: "How does one sin who does not keep what he has sworn, or vowed, that he would do?" It responds: "Of the same sin (namely, of perjury, of which discourse was had in the preceding number) is he to be judged guilty, who promises by oath that he will do something, when either he had no intention of fulfilling the promise, or, if he had, he does not in fact perform what he promises." Gerson, in his exposition of the precepts of the Decalogue, on the oath and perjury, says: "As to an oath concerning future things, a person immediately perjures himself when he has the firm will of not fulfilling it, or when he does not fulfill it in fact." St. Antoninus (Part II, tit. 10, ch. 7, on perjury, §1): "In a promissory oath, if one omits to fulfill what he promises, on account of a legitimate impediment, he is excused from mortal sin, according to Peter of Tarantasia. The same is taught by Bonaventure, on Bk. IV, dist. 39, first chapter, where he fully proves that every perjury is a mortal sin." Therefore, on the contrary, he is not excused, when a legitimate impediment is lacking. Read the whole chapter, where he fully proves that every perjury is a mortal sin. Wherefore that passage cannot be interpreted to mean that he speaks of grave, but not of small, matter. From all this it is gathered, following Augustine, Thomas, Raymond, Antoninus, the Catechism of Trent, and Gerson, that he is guilty of perjury who does not fulfill what he promised under oath. But perjury is always a mortal sin.

VI. Our opinion is established by reasons. A promissory oath, as has been said, is distinguished from an assertory one in having for its matter the truth of the future execution of the promised and sworn thing. For, by reason of present truth, it is not distinguished from the assertory oath, as the adversaries themselves confess, who all concede that a promissory oath has a twofold truth, one concerning the present, the other concerning the future. This first proposition, then, is subject to no evasion. But when the sworn and promised matter is not fulfilled, this truth proper to a promissory oath is lacking. Therefore he who swears, and does not fulfill, commits perjury.

VII. The reason adduced is entirely... established from the words of St. Thomas, who, in express words, asserts that the matter of a promissory oath is the execution of the future promised thing, just as an assertory oath has for its matter truth concerning the past or the present. "Just as an assertory oath, which is about the past or the present, ought to have truth, so too the oath concerning things to be done by us in the future ought to have truth." The Angelic Doctor adds, however, that this oath lacks truth as often as the swearer does not, at the appointed time, fulfill the sworn matter. "For one is bound to make true that which he has sworn; otherwise TRUTH IS LACKING to the oath." If truth is lacking to the oath, then the swearer calls God to witness of falsity; therefore he perjures himself; therefore he sins mortally.

VIII. All this is confirmed. The reason why the defect of truth in an assertory oath, in the lightest matter, is always a mortal sin, is that God is brought forward as witness of falsity. But, as often as the promised matter sworn by a promissory oath is not fulfilled, God is brought forward as witness of falsity. Therefore the sin is mortal. Is not a promissory oath a true oath? Therefore it invokes God for the confirmation of truth: not, however, of present truth, since in this respect it is assertory; therefore it is brought forward for the confirmation of future truth; therefore, this truth being lacking, God is called to witness of falsity.

IX. Wondrous are the responses which the adversaries offer to these evident reasons. Cárdenas responds — and this is the common response (art. 1, n. 19) — in these words: "Although, in that case, it is false that the swearer will fulfill the oath (for God knows it is not to be fulfilled), this is nonetheless not false on the part of the swearer's intention, since he has the intention of fulfilling it. Whence it is only materially false." La Croix writes this same response. See where the sharp wits of these theologians finally come down! In an assertory oath we say that Peter swears materially false, when, having applied due diligence, he swears something false, thinking it to be true. But if, through his own fault, he is ignorant of the truth, he swears formally false, though he thinks it to be true. One who does not fulfill the sworn matter, does not fulfill it through his own fault. And this we suppose as certain. For if he did not fulfill it through true incapacity, then it would be materially false. But the adversaries all speak in the hypothesis that the swearer could, and deliberately does not wish to, fulfill what he promised. Therefore, since Cárdenas and others concede that the defect of this execution induces falsity, the falsity will be formal, not material — since it draws its origin from the deliberate and culpable will of the swearer himself, unwilling to fulfill the promise.

X. Our opinion is confirmed, finally, by this. All the adversaries concede, to a man, that one who does not fulfill, in grave matter, what he promised under oath, sins mortally against the promissory oath. All equally confess, to a man, that the formal reason of any oath whatsoever is drawn not from the gravity, or the smallness, of the sworn matter, but from the invocation of divine testimony; and for this reason, commonly, besides Castropalao, and a few others, they defend, as we have seen above, that all oaths are of the same species. Finally, all affirm that a promissory oath always includes what an assertory oath has, insofar as it ought to have present truth; but it is distinguished from the assertory in this, that it invokes God for the confirmation of future truth. All this is most certain among the adversaries themselves. From which I draw this valid proof: in the violation of a promise confirmed by oath and accepted, a twofold sin is committed, in my own opinion — one against justice, the other against the oath. Into this controversy the adversaries do not draw this proposition. But the sin which is against the oath is against truth: for one cannot sin against an oath, except by sinning against truth — since the formal reason of an oath is to confirm truth, whether present, future, or past. Therefore, that the matter be grave or light does not prevent the defect of truth from always inducing a mortal sin. The magnitude of the matter constitutes a sin grave against justice, or against the fidelity of the promise; and the smallness of the same matter induces only a venial sin against that same promise. But this is wrongly thrust in to increase or diminish the malice of the oath. For the oath takes its species from truth, and is rendered good or evil by truth or falsity. Now that this truth, the single matter of the oath, falls upon a grave or a light thing matters not at all to the formal reason of the oath. Which reasoning, since the adversaries admit it in an assertory oath, they ought also to admit in a promissory oath, since both are of the same species.

XI. Hence it seems that it can be inferred that the contrary opinion is comprehended under this condemned proposition: "To call God to witness to a light lie is not so great an irreverence as to warrant that one should be unwilling, or unable, to condemn a man for it." And indeed, as we have seen, the adversaries themselves do not know how to withdraw their own opinion from the thunderbolt of condemnation, except by fleeing to a material lie, to material falsity, or to a lie against future truth. But they are mistaken. For this alone is the difference between an assertory and a promissory oath, as has often been said: that the former looks to present or past truth, the latter to future truth; or, as the Angelic Doctor says above, the former falls upon the very act of swearing, the latter upon the thing which is sworn. Now, that the invocation of divine testimony in confirmation of present or past falsity should be a mortal sin, but not so in the attestation of future falsity — this is what seems to us nearly monstrous, especially since both falsity present and future are of the same species, just as the assertory and promissory oath are of the same species.

This opinion of ours is upheld, besides Augustine, Thomas, Raymond, the Catechism of Trent, and Gerson, by Cajetan (in his Summa, s.v. Periurium, ch. 3, and II-II, q. 89, art. 3), Candido (disq. 26, art. 10, dub. 3), Filliucci (tract. 25, ch. 10, §5), Valentia (I-II, q. 8, disp. 6, punct. 3, concl. ...), Toledo (in his Summa, Bk. IV, ch. 22), Covarrubias (Bk. 1, Variae, ch. 1, n. 2), Córdoba (in his Spanish Summa, q. 335), Filiarco (On the Office of the Priest, Vol. I, tit. III, Bk. III, ch. 3), Bassaeus (Vol. I and Vol. II, s.v. Iuramentum), Sayr (Bk. I, ch. 4, n. 15, and Bk. II, ch. 22, n. 79), Medina (in his Summa, ch. 14, §4), Lessius (On Justice and Law, Bk. II, ch. 42, dub. 3), Reginaldus (Bk. I, n. 79), Bonacina (Vol. II, disp. 4, q. 1, punct. 14, n. 16), Natalis Alexander (Bk. IV, art. 3, rule 3), Genet (tract. on the 1st precept of the Decalogue, ch. 11, q. 7), Henrique a Santo Ignazio (Vol. II, Bk. X, tit. 3, conf. 14), Paolo Gabriel Antoine (tract. on the theological virtues, ch. 4, q. 5), Wigandt (tract. 10, exam. 9, n. 41).

XII. You will object with this authority of St. Thomas (II-II, q. 110, art. 3, ad 5), where he writes this: "He who promises something, if he has the intention of doing what he promises, does not lie, because he does not speak against what he holds in his mind. If, however, he does not do what he promised, he will then seem to act unfaithfully, in that he changes his mind... Whence neither did the Apostle lie, who did not go to Corinth, whither he had promised he would go." It is astonishing that this authority could be thrust upon the adversaries — drawn from q. 110, where St. Thomas has not a single word concerning an oath; whereas St. Thomas himself opposes this same authority to himself in q. 89, where he treats the oath in ten articles. In the place first cited, he objects this authority to himself, in these words (art. 7): "It seems that an oath does not have the force of obligation. For an oath is brought in to confirm the truth of what is said. But when someone says something concerning the future, he speaks the truth, even if what he says does not come to pass — as Paul, although he did not proceed to Corinth, as he had said, nonetheless did not lie." What does the holy Doctor answer to this argument? Here are his own words: "To the first, then, it must be said that one act is of a simple word, another of an oath, in which divine testimony is implored. For, as regards the truth of a mere word, it suffices that someone say what he proposes to do — for this is already true in its cause, namely, in the resolve of the doer. But an oath ought not to be employed except in a matter of which someone is firmly certain. And therefore, if an oath is employed, on account of the reverence of the divine testimony which is invoked, man is obliged to make it true, according to his own possibility, that which he swore, as has been said. What if the outcome turns to the worse?" said the Angelic Doctor in the body of the article. "Truth is lacking to the oath, unless it be lacking on this ground alone: that the sworn matter is not fulfilled at the point of death (?) — otherwise truth is lacking to the oath." The response is so manifest that it needs no further explanation.

XIII. They object with these reasons, in like manner as... those which the Fathers of Salamanca advance, who, according to their custom, merely report the arguments of other authors. They philosophize otherwise, they say, concerning the truth of an assertory oath, and the truth of a promissory one, as regards present and future truth. For the defect of the former truth is a lie, which can be honored by no reasoning. But not to keep a promised matter, sworn under oath, is not a lie, but infidelity, though it admits a smallness of matter as regards the first defect of truth in the very deed; a smallness of matter can, however, be given as regards the second truth, respecting the intention of fulfilling it — since this second falsity is not truly a lie, but infidelity.

XIV. I have wished to present this single argument of theirs in the adversaries' own words, so that the weakness of the contrary opinion may thereby be more evident. It must be answered, then, that this argument is a mere paralogism, and contains contradictory extremes. They concede that the execution of the sworn thing is the future truth of a promissory oath, since, by reason of present truth, it is assertory. Then they add that falsity is not opposed to this truth, but infidelity. Why? Because that truth is future. But we say that these mutually conflict. For, once it is conceded that the execution of the promised thing is the truth of a promissory oath, it is wrongly added that falsity is not opposed to this truth, but infidelity — since falsity is opposed to every truth, whether present, future, or past. The adversaries' argumentation, then, labors under a paralogism, precisely because they do not distinguish between the promised thing, or a simple promise, and a promissory oath. The truth of a promise, as the Angelic Doctor most excellently declares, lies in the very resolve of the one promising, not in the future execution of the promised thing. For this reason, when someone, with a true resolve, promises that he will give something, he does not sin against truth — which is really supposed in the resolve — if he does not observe what he promised, but against fidelity. But when this promised thing constitutes the matter of an oath, it takes the place of a truth confirmed by the oath; and a promissory oath, precisely as such, falls solely upon this future truth, as the Angelic Doctor says, and as the adversaries themselves concede. It is futile, then, to say that the defect of that truth is infidelity, not falsity. We answer, then, by denying the antecedent of the fabricated argument. And we say that the defect of future truth in a promissory oath constitutes perjury, just as the defect of present or past truth in an assertory oath constitutes perjury.

It is astonishing that some Cárdenas has not explained the aforesaid condemned proposition, saying that to call God to witness of a light lie, against present truth, is a mortal sin of perjury; but not so, if he is called to witness against future truth. And indeed the adversaries will assign no true difference why a defect of past truth should constitute a formal lie, but a defect of future truth a merely material lie — except that the defect of that truth proceeds solely from the fault of the promiser.

XV. They object, second: One who does not fulfill a vow in a light matter does not sin mortally; therefore neither does one who does not fulfill an oath of a light matter. Response: The consequence is denied. For there is no grave injury, or irreverence, toward God in not rendering a light matter promised, which contributes little to his honor. But to invoke God as witness of falsity, even in the lightest matter, is a most grave injury against God — because one who swears falsely in whatever manner, so far as it depends on him, brings it about that God testifies to falsity. But the veracity of God cannot be reconciled with the falsity of any matter whatsoever, however light. Therefore one who does not execute a promised and sworn thing denies the veracity of God, and, by his own endeavor, destroys it.

False, then, is the contrary opinion, which is defended by Sotus (Bk. VIII, on justice, q. 1, art. 7), Suárez (Vol. II, on Religion, Bk. III, ch. 16), Sánchez (Bk. III, Summa, ch. 4, n. 23), Tamburini (ch. 3, n. 4), Pedro Ledesma (Vol. II, tract. 14, disp. 33), Azor (Bk. XI, ch. 5), Leander (tract. 1, disp. 7, q. 2), Castropalao (tract. 17, punct. 6, n. 8), Trullench (Bk. II, ch. 1, dub. 6, n. 6), Cárdenas (dissert. 17, ch. 2, art. 2), La Croix (Bk. III, part 1, ch. 2, dub. 5, n. 304), the theologians of Salamanca (tract. 17, ch. 2, punct. 5, §2, n. 53), and others among them, who also cite John of St. Thomas in their favor (II-II, q. 88, disp. 29, art. 8); but wrongly: for this author speaks there of a vow, in which he concedes a smallness of matter; and he only calls it a probable opinion concerning an oath, without at all defending it. To the cited authors may be added Fr. Sporer (tract. on the 2nd precept of the Decalogue, sect. ..., n. 137), where he says: "In practice, I hold it altogether safe that a promissory oath is excused from mortal sin by the lightness of the matter." But all the Fathers have execrated every perjury as an accursed thing, and Augustine calls it a monstrous beast; and none of them distinguished between promissory and assertory perjury. St. Thomas, however (II-II, q. 98, art. 3), resolves that all perjury is a mortal sin. Wherefore Fr. Sporer, too confidently, established that every promissory perjury is altogether safely reckoned venial, from the smallness of the matter. But of these things enough has been said.

XVI. Question IV. Would one who, under oath, promised something with a doubtful intention of fulfilling it, sin mortally? Response: All commonly respond affirmatively. Just as one who swears a doubtful matter as certain commits assertory perjury, so too one who promises something by oath which he doubts, or does not believe, he will fulfill, sins mortally by promissory perjury. No one, then, ought to confirm his promises by a promissory oath, unless he is morally certain of the future execution. Nor do probable conjectures, or reasons, suffice; but grave and firm foundations, which remove every prudent doubt, are required — whatever some may assert to the contrary. See what has been said concerning an assertory oath.

XVII. Question V. How are those oaths to be interpreted by which men commonly swear that they will not be the first to enter through a door, or to sit, etc.? Response: These are interpreted in this manner: that the swearers have the firm resolve of fulfilling what they assert, according to the sense which such expressions convey. The common sense, however, is that the swearer, so far as it concerns himself, so far as it lies on his own part, does not wish to enter first, to sit first, etc. Wherefore, if, by another's excessive courtesy, he is compelled to enter first...

I. This condition, which is one of the three necessary for any oath whatsoever, has its chief place in a promissory oath. This justice prescribes that a lawful and honorable matter be promised under oath. Wherefore a promise of unlawful and wicked matter under oath is, by its own kind, a mortal sin. Doctors commonly hand down that the gravity of the matter which falls under the oath must be inspected, so that from this the gravity of the sin against the oath may be gathered. Certain questions will explain the whole matter.

II. Question I. Does one who swears that he will fornicate, or perpetrate any other grave crime, sin mortally against the virtue of religion? Response: All respond affirmatively, since he really has the intention of fornicating; there will be perjury, if the intention of fulfilling what he swears is lacking. Such a swearer, then, commits a twofold sin: one against truth, if the intention of fulfilling what he swears is lacking; the other against the justice of the oath, whether he has or lacks the intention of fornicating — a single, most grave sin, since to bring God forward for the confirmation of iniquity is to inflict a most grave injury on God.

III. Question II. Does one who swears that he will commit some venial sin sin mortally? Response: The common opinion is negative — since it is not a grave injury for the swearer to be bound to the commission of a venial sin. And this is established by the authority of St. Thomas himself: for it does not seem a great matter that one should compel oneself, under the confirmation of one's own resolve, to commit a venial sin, merely by the culpable fault of omitting the execution of the aforesaid oath. Thus more recent authors commonly distinguish.

IV. As for the opinion just reported, if I inspect the multitude of authors whom they cite, the Fathers of Salamanca follow it (tract. 17, ch. 2, punct. 5, n. 54), asserting it more probable; but if I weigh the reasons, I cannot but judge it improbable to me. For indeed, one who swears that he will commit a venial sin invokes God to strengthen and confirm his own resolve. Since, then, some deliberation, or resolve, is fortified by the authority of divine testimony, so that it may become firmer, and more immovable — what is more injurious to God, what more hostile, what more infamous, than to abuse the majesty of his infinite name, and to turn his authority into a support for iniquity? This is confirmed. One who swears without the intention of swearing sins gravely. Why? Because he abuses the oath. But it is a worse abuse when someone uses an oath to confirm venial iniquity. Therefore, etc. It should be added that one who invokes God as witness of a venial sin brings him forward as its surety, and approver; for a witness is summoned to testify, so that he may approve what he confirms by his testimony. What, indeed, is more wicked than to induce God to approve an iniquity, however small? Finally, it is a venial sin to take the name of God in vain — namely, if, without necessity, you swear that you will do something lawful and honorable; but if you swear that you will sin, will you sin only venially? If you swear with the intention of committing that sin, you sin mortally, since you convert the most holy name of God to the confirmation of iniquity, and profane it, and commit an enormous injury against his veracity, whose consent, he to whom every malice, however slight, is utterly repugnant, is asked.

V. Fr. Castropalao confesses that all these considerations seem difficult to him (tract. 14, disp. 1, punct. 6, n. 10); he does not dare, however, to depart from the common opinion; and therefore he offers certain contrived responses. He answers, then, that the swearer does not intend to induce God to approve the iniquity, since the end of the oath is the confirmation of truth. He who converts it, on his part, into a bond of committing iniquity, will he sin only venially? These things, surely, seem too harsh, not to say absurd. An oath, by its own nature, is a sacred thing, whose end is the confirmation of truth. One who, out of a certain vulgar ignorance, swears believing that whatever is promised under oath will be immutable — I too grant that the swearer has no such explicit intention of inducing God to approve iniquity; for, if he explicitly intended this, he would blaspheme. But we say that he does this in effect, by this very fact that he uses divine testimony. The second response, however, is not better than the first — namely, that the swearer is not bound, except under venial obligation, to avoid the preceding sin, because it would be better to avoid a venial than a mortal sin. This is true; but he ought to abstain from the invocation of divine testimony in confirmation of iniquity, even the smallest, since any malice whatsoever, however small, is supremely repugnant to God. Therefore a most grave injury is done to God, as often as he is invoked to confirm the resolve of perpetrating any iniquity whatsoever.

VI. Question III. Does one who swears he will do something against the evangelical counsels — for instance, that he will not accept a prelacy, that he will not enter religious life, and other things of this kind — sin mortally? Response: The most common opinion is that only a venial sin is committed by such a swearer. St. Thomas teaches this (II-II, q. 89, art. 7, ad 2): "If, however, someone swears that he will not do some better good, which nonetheless he is not bound to do, he indeed sins by swearing, insofar as he places an obstacle to the Holy Spirit, who is the inspirer of a good resolve; he does not, however, sin by keeping the oath; but he will do much better, if he does not keep it." Of what kind this sin is, the Angelic Doctor does not absolutely determine; he only resolves that a sin is committed, if such an oath is observed.

From this it is gathered — since it is a sin to swear the omission of a greater good — how much graver a sin it is to swear the commission of a positive iniquity, though light. Of the former kind of oaths, if you observe them, you do not sin, because you were not absolutely bound to enter religious life; but you do sin by observing the latter kind. If, however, someone omitted the execution of some evangelical counsel, for this reason chiefly, that he had sworn such an omission, he would, without doubt, sin mortally — since there would be at least a tacit error in faith, if he believed that an oath obliges to the omission of those things which conduce to the attainment of evangelical perfection.

I. What we are about to say in this chapter is easy, and open to all — since those things which we have said above concerning this matter will dispatch the whole business in a few words. A promissory oath requires two conditions to be subjected to the matter: first, that it be lawful; second, that it be possible, and good.

II. By the term "lawful matter" are understood not only spiritual things, namely acts of piety, of religion, of faith, and similar ones; but also all human affairs and business, commerce, covenants, and contracts, provided they concur... with the three conditions already explained. Hence the error of Wycliffe was condemned in the Council of Constance, who denied that it is lawful to confirm human contracts and civil commerce by oath. But of this enough has already been said.

III. From this it follows, first, that all those matters which are illicit, shameful, and culpable are excluded, since the matter of an oath ought to be lawful. The reason is manifest: because an oath is not a bond of iniquity, as all things proclaim. Wherefore an oath to commit a venial sin does not oblige in any way. And although in the chapter "Cum contingat," on the law of oaths, it is established that every oath is to be kept, unless it turns to the detriment of eternal salvation, it does not therefore follow that a venial sin may be committed. For, granted that it is lawful to commit a venial sin confirmed by oath, and that this in some way closes the door of eternal life; since, unless one is purged of it either in this or in the future age, no one attains the reward of eternal life — no oath, then, obliges to the observance of that which cannot be fulfilled without either mortal or venial sin. When, however, the sworn matter is partly lawful, partly illicit, the illicit part must be omitted; the lawful and good part, however, must be observed.

IV. Not only must the matter of a promissory oath be lawful, but possible, so that it may give rise to the obligation of execution. Wherefore an oath concerning impossible matters is rash, and empty. Those, then, sin, who promise another's deed under oath, since one cannot compel another's will. It must be observed, however, that men often, in promising another's deed, swear their own deed — for example, if you swear that Peter will marry his betrothed Bertha, or that he will pay Paul a sum of money, or other things of this kind — according to common sense, you do not swear another's deed, but your own — namely, that you will use every effort to bring it about that Peter contracts the marriage, so that he pays what is owed, etc. Hence jurists teach that such an oath has a twofold force: that it is valid in one way, if it can be fulfilled in the manner in which it sounds; in another way, if the deed of another sworn cannot be fulfilled in that manner, it is valid in whatever manner it can be. It can be sworn concerning another's deed in a twofold manner. First, enunciatively — as when you swear that you believe a sick man will regain his former health, or that tomorrow the sky will be clear. Second, under a promise, in which case you are bound to apply your effort and diligence, so that what you promised may happen, or come to pass. In these oaths concerning another's deed, authors commonly teach that the swearer is bound to diligence and effort, when the deed which is sworn is capable of diligence; but not so, when it is not established that he swore only enunciatively, that he believes it — since, if it were established that the oath was only enunciative, he would be bound to nothing.

V. It has been said that the matter of a promissory oath ought to be lawful, possible, and good. This last little word has been added, so that indifferent matter may be excluded — since an oath concerning an indifferent matter produces no obligation: both because God does not oblige to idle and vain acts, of which kind indifferent acts are; and because the exercise of an indifferent act, without reference to an honorable end, is always a venial sin, as the truer opinion teaches. And although, according to another opinion, it is not, for that reason, unfit matter for an oath — and this suffices, lest it be a vicious act.

VI. If, however, an indifferent act is directed toward an honorable end, or utility, the oath obliges — since an indifferent act, in the individual, though otherwise useless, on account of an honorable end, becomes an act of virtue. I add: when the oath is for the utility of one's neighbor, it must be observed, even though the matter sworn is indifferent, provided it is not evil in itself. The reason is that, in this case, what is primarily intended is not the indifference of the act, but the utility and advantage of the neighbor himself. Indeed, the observance of such an oath becomes an act of virtue — for it is an act of fidelity, and of veracity — and, beyond this, once the promise has been made and accepted by the neighbor, he already acquires a certain right, by force of which the swearer is bound to fulfill the promise. All this is established, and common among all. The same must be said of an oath which pertains to the swearer himself. For example: you swore that you would in no way pass through this way, because passage through it is an occasion of sin for you: although such passage, absolutely, is an indifferent act, nonetheless, clothed with such a circumstance, it becomes a good act.

VII. This too is worth noting: namely, that the matter of an oath made to God is different from the matter of an oath which is made in favor of one's neighbor. For an oath made to God agrees with a vow only in this: that it ought to be lawful and honorable; but such matter ought not to be merely good, but that which is a greater good. For a lesser good does not oblige, which cannot conduce to the grace of God. It must be judged otherwise concerning an oath made in favor of one's neighbor — for whom it is not always the greater good that pleases, but often that which is more pleasing to him. Therefore an oath concerning a lesser good, in favor of one's neighbor, obliges.

VIII. From this teaching, however, is excepted a promise confirmed by oath of contracting marriage — since this promise always includes this condition, unless I should choose a better state, namely, the religious one, as the Doctors commonly teach on the chapter "Ex publico," on the conversion of spouses. Nor does the text stand in the way, in the chapter "Cum eam," on him who had promised by oath a marriage arranged for his betrothed, where it seems to be established that a man who has sworn to take a woman in marriage cannot enter religious life unless the marriage is first contracted. For such a swearer can indeed contract marriage with the resolve of not consummating it, but of entering religious life, the bride being ignorant of such a resolve — as Suárez notes, and teaches (Bk. II, on the oath, ch. 13, n. 8) — which manner is lawful, though scarcely to be advised in practice, since it does not seem consonant with the bride's honor. For by this path she is rather deluded. As for the Pontiff's saying, in the cited chapter, that it is safer, the religion of the oath being observed, to contract marriage first, and then to migrate to religious life — this pertains to the fact that perhaps, in that case, such a contract redounded to the bride's honor, and therefore the Pontiff said it was safer to observe such a manner — not that it was unsafe to do otherwise; for, as I said, then it was perhaps better to observe such a manner. For the rest, since the condition of a better state is included in the promise, it follows that the oath ought to take on the nature of the act to which it is joined. The condition, then, included in the act of promise, is understood as included in the oath as well. Wherefore a betrothed man who has sworn can, without the bride's consent, and without a marriage contract, enter religious life. In practice, however, that manner is to be observed which is convenient, and which accords with the bride's honor, and does not impede entrance into religious life. It should be observed, however, that the Pontiff calls it "safer" and "momentary," not "safe" absolutely. If both cannot be observed, the taking up of the religious state ought to be preferred; provided that, in embracing the religious state, real regular observance flourishes.

IX. In the last place, it can be doubted whether an oath made concerning an unlawful matter needs relaxation. But the Doctors commonly teach that no relaxation is needed. For where there is no bond, no relaxation is necessary. But an oath, since it is not a bond of iniquity, produces no obligation whenever it concerns an unlawful matter. Nor does that stand in the way which is customarily opposed from the chapter "Venerabilem," on elections, §"Idem," where, concerning a certain usurper of a kingdom, contrary to an oath made, it is related that he ought to have consulted the Apostolic See — since it was doubtful whether or not that oath had been made concerning an unlawful matter. To the other objection, which is customarily raised from the chapter "Cum quidam," on the law of oaths, §"Illi vero," where it is decreed that sons are to be absolved from an oath of not speaking to, or aiding, their father and mother — we say, with the same author, that the word "absolve," in that text, signifies a declaration of the solution, or that it declares that oath to have been from the beginning null and void; various other solutions being set aside, which Suárez reports (Bk. II, on the oath, ch. 15, n. 18) — that oath, I say, was in no way truly binding, but only declaratory of the fact that no obligation existed; it did not truly dissolve the bond of an obligation.

I. Most grave is the obligation of an oath, which, as the Angelic Doctor says, draws its origin from the divine authority itself. For the swearer interposes divine testimony in confirmation of truth, whether present, or... past, or future. Wherefore the violation of a promise confirmed by oath is perjury, which is a most grave sin.

II. In oaths made to God, a vow also commonly occurs. As often as you confirm by oath a promise made to God, both a vow and an oath are present, which are two bonds of obligation; wherefore one who violated them would commit two sins. Not always, however, in a future matter to be done for God's honor is a vow present. For if you did not wish expressly to promise, but only to propose that you would do something in God's honor, and confirmed your resolve by oath, you would be bound only by the bond of the oath. From this you commonly gather that, in promises made to God and confirmed by oath, both a vow and an oath are always found; not, however, necessarily — since, as is established from the example adduced, an oath can be found without a vow. But in all promises made to men, only an oath, without a vow, is present.

III. All affirm that the obligation of an oath is most grave. Only a few things need to be said concerning the nature of this obligation. First of all, an oath obliges after the manner of a private law, which the swearer imposes upon himself; by its own kind, it obliges under mortal sin, according to all, with St. Thomas (II-II, q. 98, art. 3). This obligation is bound by the bond of divine testimony, and pertains to the virtue of religion. Two obligations, however, must be distinguished in a promissory oath: one which arises from the promise itself, valid and accepted — and this, upon precise distinction, is an obligation of justice; the other, proper to the oath itself, pertains, as we have said, to religion. Wherefore false is the teaching of Christian Wolff, a Lutheran man, who says (On Natural Law, Vol. III, ch. 4): "An oath produces no new obligation of rendering something to him to whom one swears."

IV. It is customarily asked here whether the obligation of an oath or of a vow is greater. This little question St. Thomas himself proposes (loc. cit., art. 8), and answers that we owe God a greater obligation of a vow than of an oath — namely, that we pay him what we have promised; since the obligation of a vow arises from the fidelity which is owed to God from the reverence due him; but the obligation of an oath is born from reverence owed to God: for the bond of fidelity is greater than that of reverence. And although a vow is confirmed by an oath, it is not therefore inferred that the obligation of the oath is the greater; but only that a movable thing is more firmly confirmed by two immovable things.

V. Suárez (Bk. II, on the oath, ch. 13) distinguishes this comparison of the vow with the oath, and says that, if the comparison of the vow is made with an assertory oath, the obligation of the vow is greater than that of the oath; but if the comparison of the vow is made with a promissory oath, then the obligation of the oath is greater than that of the vow. Nor does he say that St. Thomas's teaching is contrary to this, on the grounds that the Angelic Doctor speaks only of a promissory oath, not of an assertory one. The reason Suárez alleges is valid: because the obligation of not attributing falsehood to God is greater than the obligation of rendering vows to God — since the former is negative, "Thou shalt not take the name of the Lord thy God in vain"; the latter, affirmative, "Render to the Lord thy vows."

VI. I, however, interpret St. Thomas's teaching thus. If the pure notions of each obligation which St. Thomas assigns are inspected, absolutely speaking, the obligation of a vow is greater than that of an oath, for the reason he gives — namely, that the promise of a vow regards God directly; but the promise of an oath does not regard God, since, by an oath, as such, no promise is made to God himself, nor is an obligation contracted toward him, but God is brought forward only as witness of a promise, or of an assertion concerning some future act. Wherefore, if these two respects are weighed, as St. Thomas alone considers in the cited article, the former is without doubt more valid than the latter. For the rest, if the obligation of the oath is considered in relation to the truth necessary in an oath, whether assertory or promissory, the obligation of the oath seems greater than that of the vow. This can be proved a posteriori. For one who swears falsely, so far as it depends on him, makes God the author of a lie; how enormous an injury this is to God is self-evident. For this reason, in an oath, at least an assertory one, according to all, there is no smallness of matter; but every assertory perjury is a mortal sin. I have proved the same to occur in promissory perjury. Therefore the obligation of an oath, whether assertory or promissory, with respect to the truth to be subjected to the oath, is greater than the obligation of a vow. Since it is by no means so certain that a smallness of matter cannot be found in a vow; indeed, several concede that it can be found in a vow, though not in an oath.

Nor should you say that, in practice, these two respects cannot really be distinguished — since a promissory oath tends to this: that it obliges the swearer to the execution of the promised thing, which execution is the truth of a promissory oath; nothing, nonetheless, prevents the promise of the oath, absolutely, from being considered as compared with the promise of a vow; indeed, in fact the Angelic Doctor considers these two promises in relation to God directly; and, because the promise of a vow regards God more directly, it is therefore stronger, in the notion of a promise, than the obligation of an oath. For it seems, says the Angelic Doctor, a most grave irreverence toward God to institute a subject for a promise, or to render a vow. For the rest, if the obligation of the oath is considered by respect to the truth to be subjected to the oath itself, lest it turn out false, and God be invoked as witness of a lie, then the obligation of the oath seems, as I have said, greater than that of the vow. What is conceded of an assertory oath by Suárez, Sánchez, Leander, and others — though they deny it of the promissory — seems to me the same reasoning applies to both oaths. And, to defend this opinion which I have explained, the authority of the Church impels me, which declared that a smallness of matter is not given in perjury; though several authors explain this declaration of the Church concerning an assertory oath, we, nonetheless, from the very words of St. Thomas, have demonstrated above, that a smallness of matter is in no way given, either in a promissory oath, or in a vow, although this opinion has for a long time prevailed. If, however, this interpretation of ours does not please someone, let him assert what seems to him better. We embrace it, since we judge it opportune for explaining St. Thomas's teaching, from which take care never to depart, especially in those matters which depend on right reason — for his acuteness is incomparable.

VII. Question I. What intention, or resolve, is required for a promissory oath to induce an obligation? Response: That an oath depends on the intention of the swearer, so that the intention, or will, of swearing is necessary, for an oath to give rise to an obligation, is certain among all — since human actions which admit an obligation require the consent of the will; a consent which is not given by one who positively refuses to give it. Since, then, an oath induces an obligation of speaking the truth concerning a present or past matter, or of executing a future thing (which is the truth of a promissory oath), it is therefore necessary that a full consent of the will, or intention of swearing, be present. Whether this will, or intention, must be express, or implicit, actual, or virtual, will be said below, concerning the custom of swearing. This much is certain, and commonly defended by authors: that, if someone were to swear with the express will of not swearing, it would not properly, and in rigor, be an oath — just as it is certainly maintained by all, that an oath externally pronounced, without the intention of swearing, contains the irreverence of divine testimony, and inflicts an injury on God.

I SUPPOSE from quaest. 10. when such an oath is promised.

An OATH is, as it were, a private law, which man imposes on himself by promise, as Sanchez notes lib. 3. cap. 9. num. 1., and in this it is likened to a vow. Yet so, that the assertory oath is a greater and stricter law, because the obligation of the truth to be sworn pertains to the negative precept: Thou shalt not take the name of God in vain, obliging to not inflicting the gravest injury, by denying Him to be the first truth; but the law of a vow is affirmative: Pay thy vows to the Lord, and it obliges to serving the promised God; to violate this is less. Thus Suarez Tom. 2. de relig. Tract. de iuramento, lib. 2. cap. 3., Less. de Iustitia, lib. 2. cap. 42. dub. 11. num. 53.

Again, if it contain a promise made to God; it is higher, because it contains the obligation of a vow and of an oath. But if the promissory oath be considered as such, solitary, without Divine attestation, and be compared with a vow; the obligation of the vow is greater, both because the greater force of obliging is to be taken from the one to whom the promise is made: now in a vow we promise to God, from the intrinsic nature of the vow; but in a promissory oath to men, which is less. But if it include also God adduced in witness, this is greater, as I said, and I shall say again quaest. 16.

These one may gather in part from D. Bonavent. in 4. d. 38. quaest. 1. in fine, D. Thom. 2. 2. quaest. 89. art. 8., Suarez in the cited cap. 3 from num. 7., Sanchez num. 4. cap. 9.

The QUESTION, however, is what matter of a vow is necessary, that the oath oblige. This question the holy Doctor treats, asking: whether an uncautious promissory oath obliges.

It is CERTAIN, however, that a promissory oath ought to include something in the service of God, or the utility of men. And indeed, while something is promised to God, it takes on the reason of a vow, and its matter ought to be the matter of a vow, which was treated in disp. de Voto quaest. 6. et seqq. Say the same of matter against the counsels, as of not entering Religion.

It is PROVED by D. Bonav.: that oath has not the justice owed which directly impugns perfection; such is that against the counsels. Thus D. Thom. quaest. 89. art. 7. ad septimum, and the others commonly, cited by Sanchez lib. 3. cap. 9. num. 11., who adds that it is a sin to observe it, not indeed if it be observed materially, that is, not by force of the oath, for as S. Bonavent. says in corpore, and S. Thom. ad 1., he sins here by swearing, yet not by fulfilling. In the second mode, to observe by force of the oath, by not entering Religion, is a sin, because it operates by the force of an illicit thing. Therefore an oath about evil matter is invalid, although it must be declared such, as is had in cap. finali, verb. Confirmavit 22. quaest. 4. and cap. Venerabilem, de elect., as Suarez expounds lib. 2. cap. 25. num. 8., Sanchez in the cited place, num. 13. It is proved by D. Bonavent. in the arguments in the second place, both from D. Isidore; and because an oath is not a bond of iniquity.

From what has been said it will be permitted to elicit, that oaths of parents, heirs, and the like, by which they swear to punish sons, servants, etc., commonly do not oblige, which ordinarily come from anger, not from any virtue. Say the same of the oaths of boys to accuse other boys before the master, etc.

But the MATTER of the oath, which is for the utility of men, ought to be free of every fault, that it may oblige. Therefore if any fault, even venial, bubble up, it does not oblige, as is had in cap. Quamvis pactum, de pactis in 6. and cap. cum contingat de iureiurando, where the general rule is handed down: an oath given to man, which can be kept without loss of eternal salvation, is necessarily to be kept. By the name of loss, however, is understood even a venial sin, since it disposes to losing eternal life. Therefore this general rule the Abbas hands down in that cap. Cum contingat, num. 7., Sanchez lib. 1. de matrimonio, d. 12. et lib. 3. sum. cap. 9., Tañer num. 25. cum Covarru. de pact. 3. part., Molin. Tom. 1. d. 149. et tom. 2. d. 271., Lessius lib. 2. cap. 17. d. 7., with D. Bonavent. in resol. et ad argumenta.

BUT although in promises made to God it is required that the thing be of the better sort; nevertheless in matter sworn to a man it suffices if it be indifferent, as Suarez teaches lib. 3. cap. 16. et 22., Sayrus lib. 5. cap. 5. num. 5., Lessius lib. 2. de Iustitia, cap. 42. d. 4. num. 20. The reason of the diversity is, because God wills better things; but man also exacts indifferent things, provided they be useful to himself, which, although in itself the matter be indifferent, nevertheless as rendered by oath, it is reduced to virtue, as I said quaest. 4., and Sanchez notes lib. 3. cap. 11. num. 2., with Lessius lib. 2. de Iustitia, cap. 42. dub. 6. num. 26., Suarez Tomo 2. de relig. Tract. de iuram. lib. 2. cap. 16. num. 4.; and indeed Vasquez says prima. 2. d. 174. num. 35. that it is necessary that it be an act of some virtue, which is the sense of all. Yet something can be in the promise illicit matter; but licit in the rendering, as is clear of the hire of a harlot, as Valentia notes d. 5. quaest. 6. puncto 5., Sanchez loc. cit. num. 27.

From these you have the rule: Non est obligatorium; de regulis iuris in 6., where it is said: An oath against good morals does not oblige. Where Sanchez glosses: if it be against good morals, by the natural laws, the divine, or canonical precepts; because these laws tend to composing souls; but he does not speak of morals ordered by the civil law, because the civil law is ordered to political composition; nor does it always contain matter ordained under sin.

I ASSERT therefore first, that an oath, once promissory, emitted, ought to oblige.

It is PROVED by D. Bonavent. in 3. d. 39. art. 2. quaest. 1. in corpore, et in fundamentis, from Matth. 5: Thou shalt pay thy oaths to the Lord. He confirms it from D. Augustinus serm. 28. de verbis Apostoli.

It is PROVED secondly by D. Bonavent. there, and in sermone 3. Decal.: because the transgression of an oath is forbidden by the second precept: Thou shalt not take the name of God in vain, as all the Fathers assert, and the Theologians. And it is a great injury to God, by which, marked with falsity, or wickedness, or ignorance, as far as lies in the one swearing, it is sealed, as I said quaest. 4. and the three following, where I set out the three necessary companions of the oath.

I ASSERT secondly. An incautious oath, which verges into evil, or loss of salvation, is not valid.

It is CLEAR from what has been said, and it will be expounded quaest. 18.

OTHER conditions, however, are added by positive law. The first is, that the one swearing be fasting, as the holy Doctor notes d. 39. in litt. num. 8., and it is had in cap. Honestum 21. quaest. 5. and cap. 1. de testibus, et attest.; and this condition is one of counsel at least, as is had in that cap. Honestum; the Council of Orleans decreed that it be so done, except in treaties of peace, which, since they are prolonged at length, and are not to be interrupted, can be validly confirmed even by the non-fasting, as S. Bonavent. relates loc. cit. As to the time, it is required that it not be made from Advent to Epiphany, and in the Litanies of May and of the Rogations, and in the Ember Days; and from Septuagesima to the Octave of Easter, as is had in cap. Decrevit, 22. quaest. 5. But this condition has fallen into desuetude, as the Gloss teaches there, with Valentia d. 6. quaest. 7. puncto 3., Sanchez lib. 3. Decal. cap. 5. num. 4.

FURTHERMORE, an oath is forbidden to certain persons. First, Perjurers are excluded from a judicial oath cap. Parvuli 22. quaest. 1., because from the moment they have once committed perjury, they are presumed always about to commit perjury; for they are infamous, as D. Bonavent. notes d. 39. quaest. 3. in corpore, and D. Thom. quaest. 98. art. 3. ad 2. Yet that they be excluded only after they have been judicially convicted and condemned of this crime, Archid. teaches, whom Sylvest. relates and follows V. Periur. quaest. 5., Sotus lib. 8. de Iust. quaest. 1. art. 10., Aragon. 2. 2. quaest. 89. art. 10., Sanchez loc. cit. num. 5.

FURTHERMORE, boys before puberty are forbidden to swear in judgment cap. Parvuli, et cap. Pueri, 22. quaest. 1.

THIRDLY, Priests are forbidden to swear from a slight cause in judgment cap. si quis Presbyter 2. quaest. 5. D. Thomas gives the reason quaest. 89. art. 10.

IN three cases, however, clerics cannot swear in the hand of a layman without the license of their Bishop. The first is, when they swear before a layman, as compelled by him as superior. The second, when they swear upon calumny. The third, in the act of testifying. See Sanchez lib. 3. num. 8.

It is most certain among all that an oath of this kind binds. For so it is defined. lib. 2. Decret. cap. Debitores: debtors are not to be compelled to pay the usuries to which they had bound themselves; but if they have sworn to their payment: They are to be compelled to render to the Lord their oath.

The reason of D. Thomas 2. 2. quaest. 89. art. 7. ad 3. is, because, although an obligation does not arise to man, because through injury he acquires no right; nevertheless it is acquired by God, brought in as witness, insofar as he is bound to render God as a truthful witness of his promise, just as he was invoked, if the promise can be fulfilled without sin. Which reason is also general in D. Bonaventure in 3. d. 39. in the last question, in the arguments, and in the body, and more clearly in the same art. 3. quaest. 2. in the body. Now such is the payment of usuries; and if the usurer sins in receiving, the swearer does not sin in paying.

Yet truly this reason does not seem sufficient, for by the common consent of Theologians, the matter of the one swearing ought to pertain to some virtue, in order that a promissory oath bind, as I said in quaest. 13. but no virtue is found in this act: Therefore it will in no way bind.

Cajetan 2. 2. quaest. 87. art. 7. whom Soto follows lib. 8. de Iustitia, quaest. 1. art. 7. Aragon 2. 2. quaest. 89. art. 7. ad 7. conclus. 2. Valencia d. 6. quaest. 7. puncto 4. num. 1423. say that it is an act of charity toward oneself, for the one paying redeems the vexation inflicted, just as also he who promises to an urgent robber, and pays the promised money, redeems the vexation inflicted; and although at the time of payment he may be safe, nevertheless the end is still to redeem the vexation begun at the time of the promise.

Yet this reason in our case does not seem solid; for vexation is unjust coercion; but a usurer unwilling to lend is not unjust. For only in a case of necessity is he bound to lend; and that neither by justice, but by charity. Therefore a promise of paying usury is not to redeem a vexation, since none exists.

Sanchez therefore ANSWERS that that payment is an act of the great virtues of truth and fidelity, even when the promise of itself would not otherwise bind: It is also an act of preserving one's own reputation and honor, by standing by promises even in unjust extortions. But these suffice for gracing the sworn payment, although they do not suffice for binding without an oath.

Another objection against the reason of D. Thomas and D. Bonaventure seems to arise, because in cap. Debitores it is defined that they are to be compelled to payment who have sworn usuries. And thus many hold with Sanchez num. 7. that a right is acquired by the usurer, and therefore that he can by a right of action compel the swearer to stand by his promises.

Yet truly the text itself declares that the obligation is contracted with God, not with men; for it says: They are to be compelled by the Lord, that is, by God, to render the oath. And thus a Judge ex officio ought to compel him who has sworn, to fulfill the obligation contracted with God, but not at the instance of a party asserting a right of action. So Sanchez num. 8. citing others.

But he satisfies the obligation of this oath by momentary payment, and at once, without any relaxation of the oath, what has been paid can be reclaimed; it is had in cap. Ad audientiam, de his quae vi, there: Notwithstanding the aforesaid oath, by which he was bound not to reclaim, but only to resign. So the Gloss notes there, Hostiensis, Ioannes Andreas, Antonius Anchar, Abbas, and other Canonists, Suarez in that lib. 2. cap. 9. numero 16. Lessius lib. 2. de iustitia, cap. 17. d. 7. numero 51. et cap. 42. dub. 6. numero 27.

You will object first, against the principal assertion, namely that he is bound to pay the sworn usuries. If the principal obligation does not subsist, the accessory also collapses, Rule cum principalis, ff. de regulis iuris; and the oath is added to the promise of paying usuries; but the promise does not bind, as all confess: Therefore.

It is ANSWERED with the Canonists ad cap. Debitores, when an irritant cause of the principal concurs in the accessory, the accessory collapses with the principal; otherwise when it does not concur; for then the principal collapses while the accessory stands, which happens here; for the principal promise is invalid on account of the turpitude of the extorter, which is not found in the order to God, in respect of which alone the oath binds.

He ANSWERS secondly, Covarruvias de pactis, 2. part. §. 3. that this oath is not accessory to the promise, nor is it brought in to confirm it, but it is principal and standing per se, binding to fulfillment, lest God be a false witness of that promise.

You will object secondly. If this oath binds under mortal sin: Therefore a simple promise will bind under venial sin against truth; for the oath supposes it, it does not induce it.

It is ANSWERED, that both promises require truth of the present, that is, that when one swears, the will to fulfill be present; but as to truth of the future, the defect of truth is not always bad, indeed it is often good, as when a bad thing is promised.

You will object thirdly. When certain things are joined by some medium, with the medium removed the union of the extremes is taken away; but the oath and its obligation are united through the promise mediating, which is invalid: Therefore.

Sanchez ANSWERS, denying the minor, for they are joined by those media, whether they bind or not. This answer seems not to solve the difficulty.

Therefore it is ANSWERED, denying the minor, because they are joined of themselves, since the promise brings no bond.

There were some, whom St. Bonaventure reports, who thought that although an assertory oath extracted by force and unjustly is valid and binds, nevertheless a promissory oath does not bind. The Gloss also reports them cap. 2. verb. esse, de iureiurando.

It is, however, most certain that oaths of this kind bind. So St. Bonaventure here, and St. Thomas, whom all Theologians and Jurists follow, ad cap. si vero: et cap. Verum, de iure; et cap. Ad audientiam, de his, quae vi, where it is expressly defined.