Then I suppose that we ought to do good to the just and harm
to the unjust?

I like that better.

But see the consequence:--Many a man who is ignorant of human nature
has friends who are bad friends, 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.

You would argue that the good are our friends and the bad our enemies?

Yes.

And instead of saying simply as we did at first, that it is just to do