Deuteronomy 23:21-23

Darby Translation

²¹ When thou vowest a vow to Jehovah thy God, thou shalt not delay to perform it; for Jehovah thy God will certainly require it of thee, and it shall be sin in thee.

²² But if thou forbear to vow, it shall be no sin in thee.

²³ What is gone out of thy lips thou shalt keep and do, as thou hast vowed to Jehovah thy God, the voluntary-offering that thou hast promised with thy mouth.