touched the key-note of the whole work in asking for the definition of
justice, first suggesting the question which Glaucon afterwards pursues
respecting external goods, and preparing for the concluding mythus of the
world below in the slight allusion of Cephalus. The portrait of the just
man is a natural frontispiece or introduction to the long discourse which
follows, and may perhaps imply that in all our perplexity about the nature
of justice, there is no difficulty in discerning 'who is a just man.' The
first explanation has been supported by a saying of Simonides; and now
Socrates has a mind to show that the resolution of justice into two
unconnected precepts, which have no common principle, fails to satisfy the
demands of dialectic.

...He proceeds: What did Simonides mean by this saying of his? Did he
mean that I was to give back arms to a madman? 'No, not in that case, not
if the parties are friends, and evil would result. He meant that you were
to do what was proper, good to friends and harm to enemies.' Every act
does something to somebody; and following this analogy, Socrates asks, What
is this due and proper thing which justice does, and to whom? He is
answered that justice does good to friends and harm to enemies. But in
what way good or harm? 'In making alliances with the one, and going to war
with the other.' Then in time of peace what is the good of justice? The
answer is that justice is of use in contracts, and contracts are money
partnerships. Yes; but how in such partnerships is the just man of more
use than any other man? 'When you want to have money safely kept and not
used.' Then justice will be useful when money is useless. And there is
another difficulty: justice, like the art of war or any other art, must be
of opposites, good at attack as well as at defence, at stealing as well as
at guarding. But then justice is a thief, though a hero notwithstanding,
like Autolycus, the Homeric hero, who was 'excellent above all men in theft
and perjury'--to such a pass have you and Homer and Simonides brought us;