NUMBERS xxx
The general command regarding vows is that whosoever binds himself by one, or takes an oath in regard to any promise, must at all hazards keep his word. A man is allowed to judge for himself in vowing and undertaking by oath, but he is to have the consequences in view, and especially keep in mind that God is his witness. The matter scarcely admitted of any other legislation, and neither here nor elsewhere is any attempt made to lay penalties on those who broke their vows. To use the Divine Name in an oath which was afterwards falsified brought a man under the condemnation of the third commandment, a spiritual doom. But the authorities could not give it effect. The transgressor was left to the judgment of God.
With regard to vows and oaths the sophistry of the Jews and their rabbis led them so far astray that our Lord had to lay down new rules for the guidance of His followers. No doubt cases arose in which it was exceedingly difficult to decide. One might vow with good intention and find himself utterly unable to keep his promise, or might find that to keep it would involve unforeseen injury to others. But apart from circumstances of this sort there came to be such a net-work of half-legalised evasions, and so many unseemly discussions, that the purpose of the law was destroyed. Absolution from vows was claimed as a prerogative by some rabbis; against this, others protested. One would say that if a man vowed by Jerusalem or by the Law he had said nothing; but if he vowed by what is written in the Law, his words stood. The "wise men" declared four kinds of vows not binding--incentive vows, as when a buyer vows that he will not give more than a certain price in order to induce the seller to take less; meaningless vows; thoughtless and compulsory vows. In such ways the practice was reduced to ignominy. It even came to this, that if a man wished to neutralise all the vows he might make in the course of a year he had only to say at the beginning of it, on the eve of the Day of Atonement, "Let every vow which I shall make be of none effect," and he would be absolved. This immoral tangle was cut through by the clear judgment of Christ: "Ye have heard that it was said to them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: but I say unto you, Swear not at all; neither by the heaven, for it is the throne of God; nor by the earth, for it is the footstool of His feet; nor by Jerusalem, for it is the city of the great King. Neither shalt thou swear by thy head, for thou canst not make one hair white or black. But let your speech be, Yea, yea; Nay, nay: and whatsoever is more than these is of the evil one." In ordinary conversation and dealings Christ will have no vows and oaths. Let men promise and perform, declare and stand to their word. He lifts even ordinary life to a higher plane.
With regard to women's vows, four cases are made the subject of enactment. First, there is the case of a young woman living in her father's house, under his authority. If she vow unto the Lord, and bind herself by a bond in the hearing of her father and he do not forbid, her vow shall stand. It may involve expense to the father, or put him and the family to inconvenience, but by silence he has allowed himself to be bound. On the other hand, if he interpose and forbid the vow, the daughter is released. The second case is that of a woman who at the time of marriage is under a vow; and this is decided in the same way. Her betrothed husband's silence, if he hears the promise, sanctions it; his refusal to allow it gives discharge. The third instance is that of a widow or a divorced woman, who must perform all she has solemnly engaged to do. The last case is that of the married woman in her husband's house, concerning whom it is decreed: "Every vow and every binding oath to afflict the soul, her husband may establish it, or her husband may make it void.... If he shall make them null and void after he hath heard them, then he shall bear her iniquity."