Numbers 30:1-3

1Then Moses spoke to the leaders of the tribes of the Israelites, saying, “This is the thing which the Lord has commanded:

2If a man makes a vow to the Lord or swears an oath to bind himself with a pledge [of abstinence], he shall not break (violate, profane) his word; he shall do according to all that proceeds out of his mouth.

3“Also if a woman makes a vow to the Lord and binds herself by a pledge [of abstinence], while living in her father’s house in her youth,