The Republic by Plato Part 1 Page 76

unjust desires more than both his like and his unlike?

Nothing, he said, can be better than that statement.

And the unjust is good and wise, and the just is neither?

Good again, he said.

And is not the unjust like the wise and good and the just unlike them?

Of course, he said, he who is of a certain nature, is like those who are of a certain nature; he who is not, not.

Each of them, I said, is such as his like is?

Certainly, he replied.

Very good, Thrasymachus, I said; and now to take the case of the arts: you would admit that one man is a musician and another not a musician?