(i) A young unmarried woman living in her father's house (Numbers 30:3-5).
‘Also when a woman vows a vow to Yahweh, and binds herself by a bond, being in her father's house, in her youth, and her father hears her vow, and her bond with which she has bound herself, and her father holds his peace at her; then all her vows shall stand, and every bond with which she has bound herself shall stand.'
The first example was of a young woman still unmarried and living at home under her father's jurisdiction. Note that she was ‘in her youth'. She was in expectancy of marriage. Normally such a young woman would be in her early teens, or younger. When she vowed a vow it was subject to the agreement of her father. If when he first heard of it he said nothing then he was seen as approving of the vow and the vow became firm and could not afterwards be rescinded. By his silence he was seen as having given his approval. The vow stood and any bond had to be fulfilled. Note that the positive aspect comes first. Making vows of dedication was still in mind as something positive and meaningful.
‘But if her father disallow her in the day that he hears, none of her vows, or of her bonds with which she has bound herself, shall stand: and Yahweh will forgive her, because her father disallowed her.'
However, if her father immediately rescinded her vows on the day that he heard of them then none of her vows would officially stand. She would not be bound to them by God or man. And Yahweh would forgive her because it was her father's decision. She could, of course, still act in accordance with them, but the point is that neither God nor man would hold her bound to them.
This must not be assumed to be an easy get out. The father would be seen as responsible to honour vows that were made which were positive and sensible. He would not be expected to hinder his daughter's dedication to Yahweh. But the point is that the vows may have been the rash act of a young teenager, or may have affected things outside her own life. Thus the father was put in a position to decide whether they should have been made, and to confirm or deny them accordingly