Numbers 31:4
Put a thousand men in the field from each of the tribes of Israel.”
Moses told the people: “Let some of you go off to the war and attack the Midianites, for you have to carry out the Lord’s vengeance.
“Fully avenge the Israelites for what they have suffered from the Midianites. After that, you will be joined to your people.”
These are the laws the Lord gave to Moses concerning the relationship between man and wife and between a father and his daughter while she is still young and living in her father’s home.
But if he forbids them a long time after learning of them, he must suffer what results from the wife’s failure to fulfill the vow or solemn promise.”
If the husband has said nothing to her by the following day, it means that he approves or allows her vow, whatever it may be, or her solemn promise, whatever it may be. He confirms his wife’s vows by saying nothing on the day he learns of them.
Any vow or solemn promise to abstain from something the wife makes must be allowed or forbidden by the husband.
But if the husband forbids it on the day he learns of it, she is not required to do whatever she has vowed or solemnly promised. The Lord will not hold her to it.