Bamidbar (Numbers): Matot > Ch 30
Laws regarding vows. A man must keep his vow to G-d. A father can void his young daughter’s vow and a husband can void his wife’s vow if the voiding happens immediately when one learns about the vow.
Moses spoke to the children of Israel in accordance with all that the Lord had commanded Moses. Moses spoke to the heads of the tribes of the children of Israel, saying: This is the thing the Lord has commanded.
If a man makes a vow to the Lord or makes an oath to prohibit himself, he shall not violate his word; according to whatever came out of his mouth, he shall do.
If a woman makes a vow to the Lord, or imposes a prohibition [upon herself] while in her father's house, in her youth, if her father heard her vow or her prohibition which she has prohibited upon herself, yet her father remains silent, all her vows shall stand, and any prohibition that she has imposed upon herself shall stand. But if her father hinders her on the day he hears it, all her vows and her prohibitions that she has imposed upon herself shall not stand. The Lord will forgive her because her father hindered h er.
But if she is [betrothed] to a man, with her vows upon her or by an utterance of her lips which she has imposed upon herself, and her husband hears it but remains silent on the day he hears it, her vows shall stand, and her prohibition which she has imposed upon herself shall stand. But if her husband hinders her on the day he heard it, he has revoked the vow she had taken upon herself and the utterance which she had imposed upon herself, and the Lord will forgive her.
As for the vow of a widow or a divorced woman, whatever she prohibited upon herself will remain upon her. But if she vowed in her husband's house, or imposed a prohibition upon herself with an oath. and her husband heard and remained silent, and did not hinder her, all her vows shall stand, and every prohibition she imposed upon herself shall stand. If her husband revokes them on the day he hears them, anything issuing from her lips regarding her vows or self imposed prohibitions shall not stand; her husband has revoked them and the Lord shall forgive her. Any vow or any binding oath of self affliction, her husband can either uphold it or revoke it. However, if her husband remained silent from day to day, he has upheld all the vows and prohibitions she has assumed; he has upheld them since he remained silent on the day he heard it.
If he revokes them after having heard [them], he shall bear her iniquity.
These are the statutes which the Lord commanded Moses concerning a man and his wife, a father and his daughter, in her youth, while in her father's house.