The Republic by Plato Part 1 Page 26

and in that case he ought to do harm to them; and he has good enemies whom he ought to benefit; but, if so, we shall be saying the very opposite of that which we affirmed to be the meaning of Simonides.

Very true, he said: and I think that we had better correct an error into which we seem to have fallen in the use of the words ‘friend’ and ‘enemy.’

What was the error, Polemarchus? I asked.

We assumed that he is a friend who seems to be or who is thought good.

And how is the error to be corrected?

We should rather say that he is a friend who is, as well as seems, good; and that he who seems only, and is not good, only seems to be and is not a friend; and of an enemy the same may be said.