Summa contra Gentiles3.138 Chapter CXXXVIII. Against those who condemn vows

Some have thought it foolish to bind oneself by vow to obey a particular person, or to abide by any particular purpose. For, seemingly, any good action whatsoever, the more freely it is done, so much the more virtuous is it. Now the greater the necessity whereby one is bound to do a thing, so much the less freely is it done apparently. Consequently it would seem that virtuous acts are deserving of less praise through being necessitated by obedience or vow.

Now those who argue thus, apparently, know not the meaning of necessity. For necessity is twofold. There is a necessity of compulsion: and this lessens the praise due to virtue, since it is opposed to what is voluntary; for compulsion is contrary to the will.—But there is another necessity resulting from an interior inclination. This does not diminish but increases the praise due to a virtuous act: because it makes the will tend to the act of virtue more tensely. For it is clear that the more perfect is a habit of virtue, the more strongly does it make the will tend to the virtuous good, and the less liable to deflect from it. And when virtue has attained its perfect end, it brings with it a kind of necessity for good action, for instance in the Blessed, who cannot sin, as we shall show further on: and yet the will is not, for that reason, any the less free, or the act less good.

There is yet another kind of necessity arising from an end: as when a ship is said to be necessary for a man, that he may cross the sea. And it is plain that neither does this kind of necessity diminish the freedom of the will, or the goodness of actions. Rather indeed, what a man does as being necessary for an end., for this very reason is commendable, and so much the more, as the end is better.

Now, it is evident that the necessity of abiding by a vow, or of obeying a person to whom one has submitted oneself, is not a necessity of compulsion, nor one that comes from an interior inclination, but arises from direction to an end: because when a man has taken a vow it is necessary for him to do this or that, if the vow is to be kept, or obedience observed. Hence, since these ends are praiseworthy, inasmuch as thereby man submits himself to God, the necessity in question takes nothing from the praise due to virtue. In addition, we must observe that when a man does what he has vowed to do, or fulfils the commands of one to whom he has submitted himself for God’s sake, his deed is worthy of yet greater praise and reward. For sometimes one deed belongs to two vices, when the act of one vice is directed to the end of another vice: thus, when theft is committed for the purpose of fornication, the act is, in its species, one of covetousness, but in intention is one of lust. It is the same with virtues: so that the act of one virtue may be directed to another virtue: thus, when a man gives of his own, that he may be bound to another in the friendship of charity, his act, in its species, is one of liberality, but on account of its end, is an act of charity. Now, an act of this kind deserves the greater praise from the greater virtue, namely charity, than from liberality. Hence even if the act were diminished in the point of liberality, still, through being directed to charity, it will call for greater praise and reward, than an act of greater liberality not directed to charity.

Let us, then, suppose a man to do an act of virtue, by fasting, for instance, or by abstaining from venery:—if he do these things apart from a vow, it will be an act of chastity or abstinence; but if he do these things by vow then they are referred to some other virtue, to which it belongs to make vows to God, namely religion, which is a greater virtue than chastity or abstinence, since it makes us behave rightly to God. Consequently an act of abstinence or continency will be more praiseworthy in one who keeps it by vow, even though he does not take such pleasure in abstaining or in being continent, because he takes greater pleasure in a greater virtue which is religion.

Again. The most important thing in a virtue, is the due end: because the character of goodness is derived chiefly from the end. Consequently where the end is higher, even if a man be somewhat remiss in his act, his act will be more virtuous: thus, if one man proposes to go a long way for the sake of a virtuous good, and another, to go a short way, he who proposes to do the greater thing for the sake of virtue will deserve the greater praise; although he may make slower progress on the way. And if a man do something for God, he offers that act to God: but if he does it by vow, he offers God not only his act, but even his very power to act. Hence he clearly purposes to offer God something greater. Therefore his act will be more virtuous by reason of the greater good intended, although another man may appear to be more fervent in the execution.

Besides. The will that precedes the act remains virtually for the whole time that the act is carried on, and makes it praiseworthy, even when a man, while he is performing an action, no longer thinks of the purpose for which he began the action: thus, a man who undertakes a journey for God, need not think actually of God at every stage of his way. Now, it is clear that a man who vowed to do a thing, willed to do so more inflexibly than one who simply proposed to do it: since not only willed he to do it, but he willed so to strengthen himself lest he should fail to do it. Accordingly, this intention of the will renders praiseworthy the execution of the vow by reason of a certain inflexibility, even where the will is not actually directed to the deed, or is directed negligently.

Therefore that which is done by vow is more praiseworthy than what is done without a vow: other things, however, being equal.