Num 30:13-16 Every vow, and every binding oath to afflict the soul, her husband may establish it, or her husband may make it void. But if her husband altogether hold his peace at her from day to day; then he establisheth all her vows, or all her bonds, which are upon her: he confirmeth them, because he held his peace at her in the day that he heard them. But if he shall any ways make them void after that he hath heard them; then he shall bear her iniquity. These are the statutes, which the LORD commanded Moses, between a man and his wife, between the father and his daughter, being yet in her youth in her father's house.
In Numbers 30 Moses was given directions what should happen when people make "vows" or "oaths unto the Lord" to "bind his soul with a bond". If a man made such a vow, the vow/oath stood - he had to do what he said. However, if a woman made a vow/oath - it stood only if her father (if she was still living in his house) or her husband (if married when she made the vow) allowed it ("held his peace" when he heard her make the vow). If he did not allow it, the father/husband "made it void" and "the Lord shall forgive her". If the woman was not married (divorced or a widow) and the vow was made was not made when she had been married, then the vow stood. If a woman made a vow and her husband disallowed it (but later than the day she made the vow), the Bible says "he shall bear her iniquity."
This is an example of the authority structure that the woman came under - she was under the protection of her father or her husband. I guess he may disallow a vow, if it was not in her best interest.
Just an interesting observation confirming some of the principles we have been learning!