Deuteronomy 23:19-20 - Interest On Loans
19 You shall not lend for interest to your brother, interest of silver, interest of food, interest of anything that is loaned on interest. 20 You may lend on interest to a stranger, but you shall not lend on interest to your brother, so that Jehovah your God may bless you in all that you set your hand to in the land where you go to possess it.