BSD Loan interest? Bad news! Ribbis doesn’t always mean giving more money. According to Jewish law, an extra gift from the borrower to the lender, or even special treatment from him are also considered as ribbis.
This prohibition is so grave, that an interest lender breaks no less than five (!) different Torah laws. The borrower is also at fault, and so are other people who aid and abet, such as the witnesses and the guarantor.