Deuteronomy 23:20-22

Living Bible

²⁰ You may take interest from a foreigner, but not from an Israeli. For if you take interest from a brother, an Israeli, the Lord your God won’t bless you when you arrive in the Promised Land.

²¹ “When you make a vow to the Lord, be prompt in doing whatever it is you promised him, for the Lord demands that you promptly fulfill your vows; it is a sin if you don’t. ²² (But it is not a sin if you refrain from vowing!)