Aristotle (c. 384-322 BCE)
“It is proportional requital that holds the state together; because people expect either to return evil for evil – and if they cannot, feel that they have lost their liberty – or good for good, and if this is impossible no exchange can take place; and it is exchange that holds them together.”
- From The Nicomachean Ethics (Bekker page 1133a) by Aristotle, translated by J. A. K. Thomson (Penguin Classics, 2004).