Deuteronomy 23:21-22
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.
22
But if thou shalt forbear to vow, it shall be no sin in thee.
Bible text: King James Version (1769 Blayney text) · Public domain