The LORD'S people were not obliged to vows; but they were obliged, when they had at anytime made them, to their faithful observance. Ecclesiastes 5:4; Ecclesiastes 5:4.
Related Commentaries of Deuteronomy 23:21
Deuteronomy 23:21-23
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
22 But if thou shalt forbear to vow, it shall be no sin in thee.
23 That which is gone out of thy lips thou shalt keep and perform; even a freewill offering, according as thou hast vowed unto the LORD thy God, which thou hast promised with thy mouth.