John Calvin Commentary Leviticus 5:4

"Or if any one swear rashly with his lips to do evil, or to do good, whatsoever it be that a man shall utter rashly with an oath, and it be hid from him; when he knoweth of it, then he shall be guilty in one of these [things]." — Leviticus 5:4 (ASV)

Or if a soul shall swear. Guilt is also ascribed to error and ignorance when a person inconsiderately does what he has promised not to do. For the oath is not violated in that instance in a way that would be criminal,²⁶⁷ but in this very carelessness, there is enough wrongdoing, because sound religion would renew the recollection of the vow. Consequently, where no anxiety (to fulfill it) is shown, there is no serious desire to do so.

But this commandment was necessary because it might often happen that men who had pledged their faith in a vow, and had broken it in thoughtlessness, would deem themselves released from all obligation and would, in the future, give themselves up to indulgence. Whereas those who arrive at such a pitch of licentiousness harden themselves more and more, until finally they throw off all reverence for God.

God would therefore have vows kept faithfully, lest those who despised them should thus rush into impiety. If, then, anyone had thoughtlessly broken faith, he is commanded to make atonement to God—not on account of his levity, as some think (as if he had rashly promised what he was not permitted to), but on account of his neglect, because he had not been diligent to remember the vow at the proper time.

Now, if the Papists stupidly twist this text according to their custom, in order to establish the obligation of all kinds of vows, their refutation is easy: namely, that God requires this steadfastness only with respect to lawful vows duly made.

We have already understood from the teaching of Moses what the rule of pious vow-making is, from which we gather that those vows which profane God’s name are by no means to be kept. For if we begin by doing wrong, obstinacy in it is doubly wicked. In this passage, therefore, “to do evil” is not to perform any improper action, but to undertake something that would otherwise be disagreeable and burdensome to the flesh: such as to diminish domestic expenditure, or to deprive oneself of luxuries, or to determine upon abstinence from something that would gratify or profit us.

²⁶⁷ “Ce qui seroit repute a crime enorme;” which would be accounted an enormous crime. —;” which would be accounted an enormous crime. — Fr..