Numbers 30:2 If a man vow a vow unto the Lord, or swear an oath to bind his soul with a bond; he shall not break his word, he shall do according to all that proceedeth out of his mouth. 14 I MC VC

Deuteronomy 23:21 When thou shalt vow a vow unto the Lord thy God, thou shalt not slack to pay it: for the Lord thy God will surely require it of thee; and it would be sin in thee. 12 I MC VC