Marx Aq2

Payment may properly be demanded by the craftsman who make the goods, or by the merchants who transport them, for both labor in their vocation and serve the common need. The unpardonable sin is that of the speculator or middleman, who snatches private gain by the exploitation of public necessities. The true descendent of the doctrines of Aquinas is the labor theory of value. The last of the Schoolmen was Karl Marx.

R.H. Tawney, “The Sin of Avarice,” in Religion and the Rise of Capitalism