John Gill's Bible Commentary Ver. 8. But if her husband disallow her on the day that he heard it , etc.] Expresses his dislike of it; and this he does as soon as he hears it, at least that same day; according to the Jews f450 , within the space of twenty four hours: then he shall make her vow which she vowed, and that which she uttered with her lips, wherewith she bound her soul, of none effect ; by contradicting it, and forbidding the performance of it; or however by declaring to her, or to others, that it is not agreeable to his mind and will that it should be fulfilled: and the Lord shall forgive her ; excuse her performance of the vow, and not impute sin to her on that account, nor punish for the breach of it, she being under the cover of her husband, and obliged to submit to his will.
According to Jarchi, the Scripture speaks of a woman that vows to be a Nazarite; her husband hears and makes it void; but she does not know it, and transgresses her vow, and drinks wine, and is defiled with the dead, so that she has need of forgiveness, though it is made void; and if vows made void, he adds, have need of pardon, much more those that are not.
Matthew Henry Commentary
Verses 3-16 - Two cases of vows are determined. The case of a daughter in he father's house. When her vow comes to his knowledge, it is in his powe either to confirm it or do it away. The law is plain in the case of wife. If her husband allows her vow, though only by silence, it stands If he disallows it, her obligation to her husband takes place of it for to him she ought to be in subjection, as unto the Lord. The Divin law consults the good order of families. It is fit that every ma should bear rule in his own house, and have his wife and children i subjection; rather than that this great rule should be broken, or an encouragement be given to inferior relations to break those bond asunder, God releases the obligation even of a solemn vow. So much doe religion secure the welfare of all societies; and in it the families of the earth have a blessing _________________________________________________
Original Hebrew ואם518 ביום3117 שׁמע8085 אישׁה376 יניא5106 אותה853 והפר6565 את853 נדרה5088 אשׁר834 עליה5921 ואת853 מבטא4008 שׂפתיה8193 אשׁר834 אסרה631 על5921 נפשׁה5315 ויהוה3068 יסלח׃5545