21 If you make a vow to the Lord your God, do not be slow to pay it, for the Lord your God will certainly demand it of you and you will be guilty of sin.
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.
21 "If you make a vow to the Lord your God, you shall not delay fulfilling it, for the Lord your God will surely require it of you, and you will be guilty of sin
21 When you make a vow to God, your God, don't put off keeping it; God, your God, expects you to keep it and if you don't you're guilty
21 "When you make a vow to the Lord your God, you shall not delay to pay it; for the Lord your God will surely require it of you, and it would be sin to you
21 "When you make a vow to the Lord your God, be prompt in fulfilling whatever you promised him. For the Lord your God demands that you promptly fulfill all your vows, or you will be guilty of sin.
Matthew Henry's Commentary on Deuteronomy 23:21
Commentary on Deuteronomy 23:15-25
(Read Deuteronomy 23:15-25)
It is honourable to shelter and protect the weak, provided they are not wicked. Proselytes and converts to the truth, should be treated with particular tenderness, that they may have no temptation to return to the world. We cannot honour God with our substance, unless it be honestly and honourably come by. It must not only be considered what we give, but how we got it. Where the borrower gets, or hopes to get, it is just that the lender should share the gain; but to him that borrows for necessary food, pity must be showed. That which is gone out of thy lips, as a solemn and deliberate vow, must not be recalled, but thou shalt keep and perform it punctually and fully. They were allowed to pluck and eat of the corn or grapes that grew by the road side; only they must not carry any away. This law intimated what great plenty of corn and wine they should have in Canaan. It provided for the support of poor travellers, and teaches us to be kind to such, teaches us to be ready to distribute, and not to think every thing lost that is given away. Yet it forbids us to abuse the kindness of friends, or to take advantage of what is allowed. Faithfulness to their engagements should mark the people of God; and they should never encroach upon others.