A free-will offering; which though thou didst freely make, yet being made, thou art no longer free, but obliged to perform it.
Related Commentaries of Deuteronomy 23:23
Deuteronomy 23:23
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.