Sharia Banking Comes to GermanyThe underlying concept of the Islamic banking business is the Prophet Muhammad's prohibition of interest. Like Jesus in the New Testament, Muhammad took action against the usurers of his time, who exploited their contemporaries by charging them exorbitant interest, sometimes well over 100 percent. Muhammad summarily prohibited charging interest unless something was provided in return. Since the 1970s, Islamic banks have sought to satisfy this requirement by offering their customers financial services on the basis of interest-free transactions