When a man makes a vow to the LORD or takes an oath to obligate himself by a pledge, he must not break his word but must do everything he said.
References for Numbers 30:2
“When a young woman still living in her father’s household makes a vow to the LORD or obligates herself by a pledge
and her father hears about her vow or pledge but says nothing to her, then all her vows and every pledge by which she obligated herself will stand.
References for Numbers 30:4
But if her father forbids her when he hears about it, none of her vows or the pledges by which she obligated herself will stand; the LORD will release her because her father has forbidden her.
References for Numbers 30:5