Aristotle, Nicomachean Ethics
H. Rackham, Ed.

Under the perverted forms of constitution friendship like justice can have but little scope, and least of all in the worst: there is little or no friendship between ruler and subjects in a tyranny. For where there is nothing in common between ruler and ruled, there can be no friendship between them either, any more than there can be justice. It is like the relation between a craftsman and his tool, or between the soul and the body [or between master and slave¹]: all these instruments it is true are benefited by the persons who use them, but there can be no friendship, nor justice, towards inanimate things; indeed not even towards a horse or an ox, nor yet towards a slave as slave. For master and slave have nothing in common: a slave is a living tool, just as a tool is an inanimate slave.