Full Idea
People expect either to return evil for evil, or good for good, and if this is impossible no exchange can take place, and it is exchange that holds people together.
Gist of Idea
Society collapses if people cannot rely on exchanging good for good and evil for evil
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1132b34)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.183
A Reaction
This is not far from a Thomas Hobbes contract view of society, with someone being needed to enforce the justice of contracts. Many societies, though, seem to have survived despite being riddled with injustices.