The Republic by Plato Part 2 Page 32

and not merely conventional good — I would ask you in your praise of justice to regard one point only: I mean the essential good and evil which justice and injustice work in the possessors of them. Let others praise justice and censure injustice, magnifying the rewards and honours of the one and abusing the other; that is a manner of arguing which, coming from them, I am ready to tolerate, but from you who have spent your whole life in the consideration of this question, unless I hear the contrary from your own lips, I expect something better.

And therefore, I say, not only prove to us that justice is better than injustice, but show what they either of them do to the possessor of them, which makes the one to be a good and the other an evil, whether seen or unseen by gods and men.