Deuteronomy 23:21-23

DouayRheims(i) 21 When thou hast made a vow to the Lord thy God, thou shalt not delay to pay it: because the Lord thy God will require it. And if thou delay, it shall be imputed to thee for a sin. 22 If thou wilt not promise, that shalt be without sin. 23 But that which is once gone out of thy lips, thou shalt observe, and shalt do as thou hast promised to the Lord thy God, and hast spoken with thy own will and with thy own mouth.