Deuteronomy 23:21

21.When thou shalt vow a vow. The rule of vowing also pertains to the keeping of the Third Commandment, since, by vowing, men exercise themselves in the sanctification of God’s name, and to promise anything to God is a kind of swearing. For what between men is called a covenant or agreement, with respect to God is a vow; and therefore it may be fitly called a sacred engagement, which not only is made with God as its witness, but which is contracted with God Himself. We have elsewhere cursorily touched upon certain oaths, such as that of the Nazarites; but since that consecration was a part of God’s worship, I have placed it under the First Commandment. Nor indeed did Moses there treat directly of the obligation itself of the vow, but of that exercise of piety which stimulated the people to the pursuit of purity, sanctity, and sobriety. I have followed the same course as to the free-will-offerings, which were certainly for the most part votive, but I have considered what was the main thing in them without much troubling myself as to what was accessory. But now under another head Moses confirms what he taught before, that God’s name was not to be taken in vain; therefore he commands them to pay their vows, by withholding which the glory of God’s name is diminished, whilst He is Himself defrauded of His right, and the promise ratified before Him is set at nought. Moreover, it is to be observed that all the vows which were ever acceptable to God were testimonies of gratitude, lest the recollection of His benefits should fail, forgetfulness of which is too apt to steal over us. When, therefore, the saints were conscious of tardiness or listlessness in proclaiming His goodness, they made use of this aid and spur, as it were, to correct their sloth. Thus, when they asked anything of importance from God, they were often accustomed to bind themselves by some promise as a manifestation of their thankfulness. Such are the vows which Moses commands to be solemnly and faithfully paid, that they might not cheat God when they had escaped from peril or had obtained what they wished, whereas in their anxiety they had been humbly suppliant. For we know with what facility or rather levity many are hurried into making vows, who afterwards, with the same fickleness, think little of breaking their promise.

On this point, then, God justly rescues His name from contempt, and to this end demands that what has been promised to Him should be paid. But inasmuch as superstitious persons apply this, or rather wrest it indiscriminately to all vows, their error must be refuted, so that we may understand the genuine meaning of Moses. The Papists would have all vows kept without exception, because it is written, “Thou shalt not slack to pay whatever hath passed your lips.” But a definition of vows must first be given, or at least we must see what vows are lawful and approved by God; for if all vows must be effectually kept, however rashly made, of old under the Law it would have been right to kill their sons and daughters, to erect altars to idols, and thus under this pretext the whole Law of God would have been entirely brought to nought. Wherefore a distinction between vows must be laid down, unless we wish to confound right and wrong. This then is the first point, that nothing can be properly vowed to God, except what we know to be pleasing to Him; for if “to obey is better than sacrifice,” (1 Samuel 15:22,) nothing surely can be more absurd than to indulge ourselves in the liberty of serving God, each according to his own fancy. If a Jew had vowed that he would sacrifice a dog, it would have been sacrilege to pay that vow, since it was forbidden by God’s Law. But inasmuch as there is an intermediate degree between that which God has expressly prescribed and forbidden, it might be objected that it was allowable to make a vow in respect to things which are called indifferent. My reply to this is, that since the principle ought always to be maintained by the godly, that nothing is to be done without faith, (Romans 14:23,)it must ever be considered whether a thing is agreeable to God’s word, otherwise our zeal is preposterous. (312)

God formerly did not forbid many things which He still was not willing to have offered to Him in worship; and so now-a-days, although it would be lawful not to taste meat all our lifelong, still if any one should vow perpetual abstinence with respect to it, he would act superstitiously; since he would inconsiderately obtrude upon God what we gather from His word that He does not approve. Wherefore if all our vows are not reduced to this rule, there will be nothing in them right and sure. Another very gross error in the Papists may also be condemned, viz., that they foolishly promise God more than they can pay. Assuredly it is more than blind arrogance, nay, diabolical madness, that a mortal man should wish to present as if it were his, what he has not received; as if any one should vow that he would not eat during his whole life, or should renounce sleep and the necessary supports of life, by common consent he would be convicted of madness. No gift, then, can be acceptable to God, except what He in His goodness has conferred upon us. But what is done in the Papacy? Monks, and nuns, and priests, bind themselves to perpetual celibacy, and do not consider that continency is a special gift; and thus whilst none of them has regard to the measure of his ability, they wretchedly abandon themselves to ruin, or envelop themselves in deadly snares. Besides, every one should consider his vocation. A monk will vow himself to his abbot, and throw off the paternal yoke: another, who was adapted for the transaction of public business, will abandon his children under cover of the monastic vow, and thus acquire immunity, Hence it appears, that whether a vow should be kept or not, is to be estimated from the character of him that vows. But a more gross and more common error is committed in respect to the object of vows. I said above that the godly never made vows to God, except in testimony of gratitude; whereas almost all the vows of the superstitious are so many fictitious acts of worship, having no other aim than to propitiate God by the expiation of sin, or to acquire favor meritoriously. I will not pursue at length those more detestable hallucinations whereby they defile themselves and their vows, when they substitute their idols in God’s place; as for instance, when a man vows (313) an altar to Christopher or Barbara. To sanction this barbarous impiety, this passage of Moses is alleged, which certainly contains something quite different, viz., that those who vow to any other being, pervert the worship of God; and in which also Moses takes it for granted that a vow is not accounted legitimate, except what is made to God Himself in accordance with the rules of religion and the prescription of the Law. Thus in this exordium the doctrine is laid down, that guilt is incurred unless what is promised is paid.