Charles Ellicott Commentary Numbers 30:3

"Also when a woman voweth a vow unto Jehovah, and bindeth herself by a bond, being in her father`s house, in her youth," — Numbers 30:3 (ASV)

If a woman also ... — Four distinct cases are contemplated in the following verses regarding vows taken by women:

1. The case of an unmarried woman, living in her youth in her father's house.
2. The case of a woman who is unmarried at the time of making a vow but enters into marriage before the vow is fulfilled.
3. The case of a widow or a divorced woman.
4. The case of a married woman.

The sanctity and obligations of the fifth commandment are distinctly recognized and enforced in these verses. (See Matthew 15:4-5.) Whenever her father heard of the vow the young daughter had made, he had the power either to ratify or to nullify it. If he remained silent, the vow was ratified; if he nullified the vow, the obligation to fulfill it was no longer in force.