Aristotle understood that money is sterile; it doesn’t beget more money the way cows beget more cows. He knew that "Money exists not by nature but by law":
"The most hated sort (of wealth getting) and with the greatest reason, is usury, which makes a gain out of money itself and not from the natural object of it. For money was intended to be used in exchange but not to increase at interest. And this term interest [the word tokos, which in Greek also means 'breed' or 'offspring']*, which means the birth of money from money is applied to the breeding of money because the offspring resembles the parent. Wherefore of all modes of getting wealth, this is the most unnatural." (1258b, POLITICS)
And he really disliked usurers:
"...those who ply sordid trades, pimps and all such people, and those who lend small sums at high rates. For all these take more than they ought, and from the wrong sources. What is common to them is evidently a sordid love of gain..." (1122a, ETHICS)
* Shakespeare thus speaks of interest as a 'breed for barren metal', when he makes Antonio ask Shylock: When did friendship take / A breed for barren metal of his friend?
Aristotle on Interest / Usury Theory of the Household Book One Chapter Ten