These verses are about the vow of a young, unmarried woman who still lives with her father at home. If her father hears it and remains silent, he agrees by his silence and the vow is valid. However, if her father forbids her to comply with the vow, so refuses to agree, then the vow is not valid. She has promised something that she is unable to keep.
Then the grace of the LORD shines: The LORD will forgive her words spoken too quickly (verses 5,8,125But if her father should forbid her on the day he hears [of it], none of her vows or her obligations by which she has bound herself shall stand; and the LORD will forgive her because her father had forbidden her.8But if on the day her husband hears [of it], he forbids her, then he shall annul her vow which she is under and the rash statement of her lips by which she has bound herself; and the LORD will forgive her.12But if her husband indeed annuls them on the day he hears [them], then whatever proceeds out of her lips concerning her vows or concerning the obligation of herself shall not stand; her husband has annulled them, and the LORD will forgive her.). She has thought she would please God, but has not been aware of her incompetence and submissive position. She should have consulted her father first. If her vow contains anything disadvantageous for the family, her father will be able to release her from that promise. All that she can promise belongs to her father.
She shows her obedience to her father by refraining from keeping her vow. The obedience to her father is so highly appreciated by the LORD that He forgives her. She needs forgiveness because her good intentions were not according to the will of God. She thought she was doing a service to God, while she did not think about the bad consequences of her vow for the family.
In general, for a woman who makes a vow, its validity depends on what the man under whom she stands does with it. God gives each person a responsibility that is in accordance with their position. God expects the man who is the head of the woman (1Cor 11:33But I want you to understand that Christ is the head of every man, and the man is the head of a woman, and God is the head of Christ.) to know his responsibility.
The relation of the woman to the man may be that of a daughter to her father (verses 3-53“Also if a woman makes a vow to the LORD, and binds herself by an obligation in her father’s house in her youth,4and her father hears her vow and her obligation by which she has bound herself, and her father says nothing to her, then all her vows shall stand and every obligation by which she has bound herself shall stand.5But if her father should forbid her on the day he hears [of it], none of her vows or her obligations by which she has bound herself shall stand; and the LORD will forgive her because her father had forbidden her.) and that of a wife to her husband (verses 6-86“However, if she should marry while under her vows or the rash statement of her lips by which she has bound herself,7and her husband hears of it and says nothing to her on the day he hears [it], then her vows shall stand and her obligations by which she has bound herself shall stand.8But if on the day her husband hears [of it], he forbids her, then he shall annul her vow which she is under and the rash statement of her lips by which she has bound herself; and the LORD will forgive her.; 10-15). In the woman we see a picture of Israel. The LORD is in relation with Israel as a Father – “for I am to Israel a Father” (Jer 31:99“With weeping they will come,
And by supplication I will lead them;
I will make them walk by streams of waters,
On a straight path in which they will not stumble;
For I am a father to Israel,
And Ephraim is My firstborn.”
) – and also as a Husband (Jer 31:32b32not like the covenant which I made with their fathers in the day I took them by the hand to bring them out of the land of Egypt, My covenant which they broke, although I was a husband to them,” declares the LORD.).
Israel has also made vows to God. The people have said three times: “We will do everything the LORD has said” (Exo 19:88All the people answered together and said, “All that the LORD has spoken we will do!” And Moses brought back the words of the people to the LORD.; 24:3,73Then Moses came and recounted to the people all the words of the LORD and all the ordinances; and all the people answered with one voice and said, “All the words which the LORD has spoken we will do!”7Then he took the book of the covenant and read [it] in the hearing of the people; and they said, “All that the LORD has spoken we will do, and we will be obedient!”). And God has kept silent. He has never overruled the promise, but on the contrary he has confirmed it by giving the people the law. Israel is still responsible for the vows with which it has committed itself to God. God has not overruled the vows in His government, that the people may learn what is in their hearts.