The Republic by Plato
I was going to say something in answer to Glaucon, when Adeimantus, his brother, interposed: Socrates, he said, you do not suppose that there is nothing more to be urged?
Why, what else is there? I answered.
The strongest point of all has not been even mentioned, he replied.
Well, then, according to the proverb, `Let brother help brother'-- if he fails in any part do you assist him; although I must confess that Glaucon has already said quite enough to lay me in the dust, and take from me the power of helping justice.