It is here taken for granted that all such persons as are sui juris - at their own disposal, and are likewise of sound understanding and memory, are bound to perform whatever they vow that is lawful and possible; but, if the person vowing be under the dominion and at the disposal of another, the case is different. Two cases much alike are here put and determined: -
I. The case of a daughter in her father's house: and some think, probably enough, that it extends to a son likewise, while he is at home with his father, and under tutors and governors. Whether the exception may thus be stretched I cannot say. Non est distinguendum, ubi lex non distinguit - We are not allowed to make distinctions which the law does not. The rule is general, If a man vow, he must pay. But for a daughter it is express: her vow is nugatory or in suspense till her father knows it, and (it is supposed) knows it from her; for, when it comes to his knowledge, it is in his power either to ratify or nullify it. But in favour of the vow, 1. Even his silence shall suffice to ratify it: If he hold his peace, her vows shall stand, Num 30:4. Qui tacet, consentire videtur - Silence gives consent. Hereby he allows his daughter the liberty she has assumed, and, as long as he says nothing against her vow, she shall be bound by it. But, 2. His protestation against it shall perfectly disannul it, because it is possible that such vow may by prejudicial to the affairs of the family, break the father's measures, perplex the provision made for his table if the vow related to meats, or lessen the provision made for his children if the vow would be more expensive than his estate would bear; however, it was certain that it was an infringement of his authority over his child, and therefore, if he disallow it, she is discharged, and the Lord shall forgive her, that is, she shall not be charged with the guilt of violating her vow; she showed her good-will in making the vow, and, if her intentions therein were sincere, she shall be accounted better than sacrifice. This shows how great a deference children owe to their parents, and how much they ought to honour them and be obedient to them. It is for the interest of the public that the paternal authority be supported; for, when children are countenanced in their disobedience to their parents (as they were by the tradition of the elders, Mat 15:5, Mat 15:6), they soon become in other things children of Belial. If this law be not to be extended to children's marrying without their parents' consent so far as to put it in parents' power to annul the marriage and dissolve the obligation (as some have thought it does), yet certainly it proves the sinfulness of it, and obliges the children that have thus done foolishly to repent and humble themselves before God and their parents.
II. The case of a wife is much the same. As for a woman that is a widow or divorced, she has neither father nor husband to control her, so that, whatever vows she binds her soul with, they shall stand against her (Num 30:9), it is at her peril if she run back; but a wife, who has nothing that she can strictly call her own, but with her husband's allowance, cannot, without that, make any such vow. 1. The law is plain in case of a wife that continues so long after the vow. If her husband allow her vow, though only by silence, it must stand, Num 30:6, Num 30:7. If he disallow it, since her obligation to that which she had vowed arose purely from her own act, and not from any prior command of God, her obligation to her husband shall take place of it, for to him she ought to be in subjection as unto the Lord; and now it is so far from being her duty to fulfil her vow that it would be her sin to disobey her husband, whose consent perhaps she ought to have asked before she made the vow; therefore she needs forgiveness, Num 30:8. 2. The law is the same in case of a wife that soon after becomes a widow, or is put away. Though, if she return to her father's house, she does not therefore so come again under his authority as that he has power to disannul hew vows (Num 30:9), yet if the vow was made while she was in the house of her husband, and her husband disallowed it, it was made void and of no effect for ever, and she does not return under the law of her vow when she is loosed from the law of her husband. This seems to be the distinct meaning of Num 30:10-14, which otherwise would be but a repetition of Num 30:6-8. But it is added (Num 30:15) that, if the husband make void the vows of his wife, he shall bear her iniquity; that is, if the thing she had vowed was really good, for the honour of God and the prosperity of her own soul, and the husband disallowed it out of covetousness, or humour, or to show his authority, though she be discharged from the obligation of her vow, yet he will have a great deal to answer for. Now here it is very observable how carefully the divine law consults the good order of families, and preserves the power of superior relations, and the duty and reverence of inferiors. It is fit that every man should bear rule in his own house, and have his wife and children in subjection with all gravity; and rather than this great rule should be broken, or any encouragement given to inferior relations to break those bonds asunder, God himself would quit his right, and release the obligations even of a solemn vow; so much does religion strengthen the ties of all relations, and secure the welfare of all societiesd, that in it the families of the earth are blessed.

And her husband heard it, and held his peace at her in the day that he heard it,.... The vow she made, and by his silence consented to it:

then her vows shall stand, and her bonds wherewith she bound her soul shall stand; or she be under obligation to perform them.

If a woman also vow a vow unto the Lord, and bind herself by a bond, being in her father's house in her youth--Girls only are specified; but minors of the other sex, who resided under the parental roof, were included, according to Jewish writers, who also consider the name "father" as comprehending all guardians of youth. We are also told that the age at which young people were deemed capable of vowing was thirteen for boys and twelve for girls. The judgment of a father or guardian on the vow of any under his charge might be given either by an expressed approval or by silence, which was to be construed as approval. But in the case of a husband who, after silence from day to day, should ultimately disapprove or hinder his wife's vow, the sin of non-performance was to be imputed to him and not to her [Num 30:15].