PLATO'S REPUBLIC There are two sorts of wealth-getting, as I have said; one is a part of household management, the other ... most hated sort, 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, which means the birth of money from money, is applied to the breeding of money because the offspring resembles the parent. Wherefore of any modes of getting wealth this is the most unnatural. http://arts.cuhk.edu.hk/~hkshp/wclassic/aristotle-politics.htm