Article III: On the Obligation of Vow

S. Th. II-II, q. 88, a. 3 and 7.

722. The intrinsic and formal effect of every vow is an obligation in conscience, from the virtue of religion, to furnish the things promised. - It is a proposition certain by faith and reason.

It is proved: From fidelity a man is bound to pay that which he has promised; but he especially owes fidelity to God, both by reason of dominion and by reason of benefit received; therefore from fidelity toward God he is especially obliged to fulfill the vows made to Him. Moreover, fidelity toward God pertains to the worship owed to Him and consequently to the virtue of religion. - This obligation is expressly stated in the Scriptures: Deut. XXIII, 21-23; Lev. XXVII, 2; Ps. LXXV, 12; Eccl. V, 3; and in law, can. 1307, § 1.

Therefore violation of a vow is a sin against religion; and indeed against it alone, unless the work was already commanded from elsewhere, as chastity. Yet of itself it is not sacrilege, because it is not the violation of a sacred thing: for a vow of itself does not render either the person vowing or the matter vowed truly sacred. But it is a sin of infidelity, that is, of perfidy toward God.

But since in all vows reverence and fidelity owed to God are of the same account, per se violations of vows in any matter whatsoever are of the same moral species; for which reason it is not necessary that the matter of the violated vow be declared in confession.

723. The obligation of a vow is grave from its genus, because it arises from fidelity toward God (I Tim. V, 11, 12). Nevertheless it is light a) always in matter altogether light, because no one is able to oblige himself beyond the capacity of the matter; b) even in grave matter, if someone obliged himself only under light obligation, because a vow does not oblige beyond the intention of the one vowing.¹

¹ By the nature of the thing and the will of the Church, exception is made for the vow emitted in sacred ordination or in religious profession.

But if he did not think about this, generally he is presumed to have obliged himself according to the quantity of the matter. Grave matter is that which conduce notably to the worship of God, or to the utility of neighbor or of the one vowing himself, whether from itself or from the circumstances, or is usually prescribed under grave obligation by natural, divine, or ecclesiastical law, for example, fasting, Mass, communion, confession.²

² This is the general rule handed down through the centuries; but now, after Noldin, Th. M. II, n. 215, some think that the rule is not to be strictly applied when not a singular action but a series of actions or a habitual manner of acting is promised after the manner of one thing: then, namely, the omitted matter is to be considered not absolutely but relatively to the whole thing promised, and thus an action notable in itself ought to be judged a modest part from the promised series. Hence one who after the manner of one thing vows for the whole month daily hearing of Mass or assistance at Marian devotion is not to be judged guilty of mortal sin if he omits it once or twice (provided, he says, it is less than a fourth part!), since he has fulfilled the promise substantially. Certainly so, if the one vowing intended in this way to oblige himself only under light obligation to such a part; but such an intention cannot be presumed, because this estimation is established neither from the nature of the thing nor from custom.

It should be noted that several light omissions coalesce into one grave omission if several things are vowed after the manner of one matter to be fulfilled several times, but not if they are vowed after the manner of several things and singly. Unless the one vowing intended otherwise, they are not accustomed to coalesce in personal vows, they are accustomed to coalesce in real vows; nevertheless disparate things: fasting, Mass, meditation, rosary, etc., do not coalesce unless they are vowed by the same vow for the same end, for example, one vowing various spiritual exercises for a month.

724. A vow cannot be fulfilled without the intention of the one vowing; hence if, explicitly or equivalently, someone positively intends not to satisfy, he remains obliged, because in acts which depend totally upon the one operating, the act does not operate beyond his intention.

Nevertheless there is not required 1. a formal and explicit intention, but it suffices that someone, even unmindful of the vow, do the prescribed work: for everyone before he makes gifts is judged first to furnish debts; nor 2. the special final intention of the one vowing or of the promised work, for example, that fasting be done for penance, alms for the glory of God, because ordinarily it does not fall under the obligation of the vow; nor 3. that it be fulfilled in the state of grace, from love of God, or from a supernatural end, unless the one vowing specially obliged himself to this.

725. The obligation of a doubtful vow. - In doubt concerning the existence of a vow, whether a vow was emitted, if after serious examination the doubt remains, the vow is judged not to be present. In doubt concerning the obligation of a vow, that is, concerning its validity or fulfillment, whether the vow was valid or was fulfilled, if the doubt is negative or light, that is, if there are light reasons for thinking that it does not oblige because perhaps it is invalid or already fulfilled, the obligation of fulfilling remains; but if, after diligent examination, a grave and positive doubt perdures, from the indirect principles of Probabilism it can be judged that no obligation is present: nevertheless dispensation is better sought.

But if one doubts concerning the mode of fulfilling, first the intention of the one vowing is to be investigated, then the words by which the promise was made, the nature of the thing promised, and the common usage and sense of the faithful; but if nevertheless the doubt remains, the one vowing may choose the mode of fulfilling which pleases him.

Hence, unless he intended otherwise: one vowing fasting is bound as the faithful in the region are accustomed to fast; one vowing fasting on each Saturday is not bound to fast if the Nativity of the Lord falls on Saturday; one who vowed fasting for an entire week is not bound on that day on which he must undertake such hard labors that he is excused from fasting; one who vowed an undetermined quantity is bound to the minimum among those things which befit God.

726. From a vow only the one vowing is formally obliged. - For by his vow he cannot oblige another, because no one can promise the thing or action of another, not even of those especially conjoined, as sons or subjects.

Yet someone can be obliged from elsewhere to execute the same work, whether from human fidelity, as if he promises that he will fulfill the vow of another; or from obedience, as if a father vows that he will hear Mass with his children and commands this to them; or from justice: thus an heir, after all things due to others and to himself have been paid (among which St. Alphonsus enumerates the legitimate portion of the inheritance owed to a son by law), before all legacies, even pious ones, is bound to fulfill the real vows of the deceased (can. 1310, § 1 and 2).

The one vowing is bound to execute personal vows through himself, nor can he do this through another: the act does not extend itself beyond the intention of the one vowing; - real vows he can fulfill through another, yet from his own goods, for example, by commanding him, or by holding his act ratified.

727. The one vowing is bound to fulfill the vow at the time determined by himself; when this time has passed, he is still bound, if by intention he established the time for urging the obligation; but if for ending it, the obligation ceases but the vow was violated. But if the intention is unknown, the time is judged to have been determined for urging the obligation in real vows, for example, a vow of giving alms for a month; but in personal vows for ending it, for example, a vow of fasting on Saturday: thus unless from the nature and end of the vow it must be established otherwise, as if someone for amendment vows to confess for a week, or in thanksgiving vows to fast on a certain day, or, on the contrary, to offer candles for a certain solemnity.

One vowing who has determined no time is bound to fulfill as soon as he morally and conveniently can, which is to be judged according to the matter and common estimation: a delay is grave which notably diminishes the matter promised, for example, if entrance into religion is deferred for a long time; but if the matter of the vow is not diminished by delay, probably even a long delay is only venial, unless it includes danger of not fulfilling the vow.

One who foresees an impediment is bound to anticipate it, provided the time of fulfilling has now begun, for example, a vow of fasting once in this week or of making a pilgrimage within this month.

728. The obligation of a conditioned vow. - On the part of affection a vow is pure if it has been emitted solely from love of the thing promised and of the honor of God; - not pure if another end is joined, for example, of obtaining conversion. Now on the part of the affection by which it is vowed and of the form by which it is expressed, one vow is absolute, circumscribed by no condition, by which the thing is promised simply in the present; - another is conditioned, by which a thing is promised under an extrinsic condition concerning a future contingent thing, suspensive or resolutory, and which, when the condition has been fulfilled, is either perfected or dissolved, for example, a vow of alms if an inheritance is obtained from a parent, or unless adverse fortune comes, a vow of religious life if a sister consents or unless the sister dies. Yet a vow to which a day is merely joined is not to be judged conditioned, for example, I will bid farewell to the world if my parents have died: for such a condition is necessary, not contingent; it is the same as saying: when they die.

A vow under a suspensive condition:

1. Obliges to furnishing the thing promised when the condition has been truly fulfilled: for then it passes into an absolute vow; it need not be observed a) before the condition has been fulfilled, nor b) if the condition is fulfilled not formally but only equivalently: thus one vowing entrance into religion if his sister marries is not bound if she dies, even if the reason of the condition added was the sustenance of the sister, unless however another intention of the one vowing were clear.

2. Obliges one not maliciously and fraudulently to impede the condition; hence a) if the condition is evil, as in a merely penal vow, the one vowing can, indeed is bound to, avoid the fulfillment of the condition; b) if the condition depends upon the will of the one vowing and is a free thing, for example, alms if the first prize is obtained, the one vowing can licitly not fulfill the condition: for he is bound by no precept to place the condition; c) if it depends upon the will of another and is a free thing, for example, entrance into religion if the father consents, he cannot licitly impede the condition by unjust means, such as force, threats, fraud; he can do so by just means, such as persuasions; d) if the condition depends partly upon natural causes, for example, fasting on such a day if convalescence has been obtained, he cannot studiously impede the causes from fulfilling the condition.

3. It does not oblige to furnishing the thing promised if the one vowing illicitly impeded the fulfillment, although in this case he sinned against the vow.

729. The obligation of a penal vow. - One conditioned vow is simply such, another penal, if under the condition of fault a penalty is promised. This can be emitted as one vow, purely penal, or a simple promise of penalty, for example, a vow of alms if someone either plays or makes himself drunk; or as a twofold copulative vow, or a promise of a better good with the sanction of a penalty to be undergone if it is not fulfilled, for example, a vow of not playing or of hearing Mass under penalty of alms.

A penal vow does not oblige to the penalty if the transgression was inculpable or only venially culpable, at least insofar as it is a transgression of the vow, in the case in which it was copulative, as if one vowing to hear Mass on Sunday omits it while not thinking of the vow: for no one is judged to oblige himself to a penalty, especially a grave one, on account of no or light fault. On the contrary, if the vow is not only penal but rather medicinal, so that someone may become more cautious and watchful in avoiding something or eradicating a custom, for example, if he promises alms as often as he blasphemes.

730. The obligation of an alternative or disjunctive vow. - On the part of mode, a vow is determinate if a certain and definite thing is promised or accurately designated; or disjunctive or alternative, by which an option among several remains if, from several things, one thing to be furnished is promised after the manner of one thing, for example, a vow of hearing Mass or of giving alms. Such a vow:

1. If it is valid, can and must be fulfilled a) per se, in one or the other matter, according to the choice and determination of the one vowing; b) per accidens in one matter (for example, Mass), in the case in which the one vowing by as it were a new vow has so determined himself that he willed absolutely to transfer the whole obligation into that matter: for then the vow is no longer disjunctive.

2. It need not be fulfilled a) if the matter determined in this way becomes impossible; indeed b) if, with such a determination not made, one part becomes evil, vain, or impossible, and thus the faculty of choosing does not remain, while however the intention of the one vowing was to determine himself freely to some part; on the contrary c) it must be fulfilled in the possible matter if the intention was to determine himself in any case whatever, or if by his own will one part becomes impossible: for then he is judged to have wished to choose the other, which is still possible.

3. It is invalid from the beginning if either matter is not apt, for example, evil or vain or impossible, because someone cannot be equally obliged to a good thing and an evil thing, for example: I will steal or enter religion.

731. Corollary. - From the foregoing, practical rules for the interpretation of vows can easily be deduced.