Aristotle: Money produces nothing

From Aristotle and Economics by Richard M. Ebeling in Capitalism Magazine:

Aristotle condemned the earning on interest on money that was lent to others. Since money is only a medium of exchange, the facilitation of trading one commodity for another, all that a lender of money could “justly” ask for was a return of the sum – the “principle” – that had been lent.

In itself money was not productive, and as such, it should not be allowed to “breed” (obtain an amount in excess of the original amount lent), because, in his mind, this would be getting something for nothing. That which was “barren” (money) could not bare “offspring” (interest on a loan).