Article II: On a Promissory Oath

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.