Deuteronomy 23:20 in the King James Version
Unto a stranger thou mayest lend upon usury; but unto thy brother thou shalt not lend upon usury: that the LORD thy God may bless thee in all that thou settest thine hand to in the land whither thou goest to possess it.
Context
19 You shall not lend on interest to your brother: interest of money, interest of food, interest of anything that is lent on interest.
20 You may charge a foreigner interest; but you shall not charge your brother interest, that the LORD your God may bless you in all that you put your hand to, in the land where you go in to possess it.
21 When you vow 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.