When did Christianity abolish rules against Christians charging interest on loaned money (usury)?
Interest on loaned money is not wrong. If your brother is in dire need and you supply money to help you either give it to him or not charge interest as he is in need. Exodus 22:25 – loan to one in need. If he wants to borrow money to build bigger barns (expand his property ) or do business then charging an agreed amount of interest is OK. Usury is when an interest rate is charged that is too high or not mutually agreed.