It was mostly illegal in Christian medieval Europe to charge interest on a loan of money, for much the same reasons Islamic law forbids it: That, as money is intrinsically unproductive, it is ethically wrong to make money from money.

FORBES: Magazine Article

You've got to tell the college student, we're going to have to charge you higher interest rates on your student loan or you're just going to get smaller student loans.

WHITEHOUSE: President Obama Speaks on the Buffett Rule