Article II. On the Obligation of a Promissory Oath

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.

313. Questions. Q. 1. Whether smallness of matter is given in the transgression of a promissory oath?

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

The second opinion affirms it, because in a promissory oath God is not properly brought in as witness of the future execution of the promised thing, but only of the actual promise, or of the true intention of executing the promise ². Suarez, Navarrus, Laymann, etc. - St. Alphonsus in the Work, n. 173, says that each opinion is probable; but in the Homo apostolicus, n. 13, he adheres more to the second opinion and says: "If the thing promised is not grave, infidelity does not reach grave fault."

² This reason, from what was just said (note a, p. 307), seems less firm; for the obligation of religion, of which the author speaks at n. 312, I, does not consist merely in not lying when the promise is made (in which, certainly, there would never be light fault), but also in fulfilling the promise. Therefore one must rather have recourse to the nature of the obligation from religion, which admits smallness of matter. And indeed, if this is admitted in the violation of a promise made to God by vow, it does not appear why it cannot be admitted in a promise for which God has in some way been summoned as surety.

Q. 2. Whether a promissory oath emitted by error or deceit obliges?

Resp. It is denied, if the error or deceit concerns the substance of the matter; 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, n. 175 ³.

³ Nevertheless the same St. Alphonsus observes (lib. 3, n. 187) that the opposite opinion is probable when the error or deceit concerns those circumstances, even if accidental, which, if they had been known from the beginning, would have deterred from the oath and promise. And this observation of St. Alphonsus ought to hold just as in vows, so in gratuitous contracts, but not in onerous contracts; otherwise, as we shall see in the tract on contracts, contracts would have to be dissolved too often, since errors of this sort occur everywhere, or can be alleged as a pretext.

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.