Deuteronomy 23:19-21

Revised Standard Version Catholic Edition

¹⁹ “You shall not lend upon interest to your brother, interest on money, interest on victuals, interest on anything that is lent for interest. ²⁰ To a foreigner you may lend upon interest, but to your brother you shall not lend upon interest; that the Lord your God may bless you in all that you undertake in the land which you are entering to take possession of it.

²¹ “When you make a vow to the Lord your God, you shall not be slack to pay it; for the Lord your God will surely require it of you, and it would be sin in you.