And yet I cannot refuse to help, while breath and speech remain to me; I am afraid that there would be an impiety in being present when justice is evil spoken of and not lifting up a hand in her defence.

And therefore I had best give such help as I can.
Glaucon and the rest entreated me by all means not to let the question drop, but to proceed in the investigation.

They wanted to arrive at the truth, first, about the nature of justice and injustice, and secondly, about their relative advantages.

I told them, what I really thought, that the enquiry would be of a serious nature, and would require very good eyes.

Seeing then, I said, that we are no great wits, I think that we had better adopt a method which I may illustrate thus; suppose that a short-sighted person had been asked by some one to read small letters from a distance; and it occurred to some one else that they might be found in another place which was larger and in which the letters were larger--if they were the same and he could read the larger letters first, and then proceed to the lesser--this would have been thought a rare piece of good fortune.
Very true, said Adeimantus; but how does the illustration apply to our enquiry?
I will tell you, I replied; justice, which is the subject of our enquiry, is, as you know, sometimes spoken of as the virtue of an individual, and sometimes as the virtue of a State.
True, he replied.
And is not a State larger than an individual?
It is.
Then in the larger the quantity of justice is likely to be larger and more easily discernible.