Karl Marx: The surplus value, or that part of the total value of the commodity in which the surplus labour or unpaid labour of the working man is realized, I call profit. The whole of that profit is not pocketed by the employing capitalist. The monopoly of land enables the landlord to take one part of that surplus value, under the name of rent, whether the land is used for agricultural buildings or railways, or for any other productive purpose. On the other hand, the very fact that the possession of the instruments of labour enables the employing capitalist to produce a surplus value, or, what comes to the same, to appropriate to himself a certain amount of unpaid labour, enables the owner of the means of labour, which he lends wholly or partly to the employing capitalist — enables, in one word, the money-lending capitalist to claim for himself under the name of interest another part of that surplus value, so that there remains to the employing capitalist as such only what is called industrial or commercial profit. https://wordsmith.social/protestation/quotes#quote5646