Hi. Here are a couple of quotes by philosopher Antisthenes, a pupil of Socrates, suitable for use in the game:
"One should attend to one's enemies, for they are the first persons to detect one's errors."
"It is better to fight with a few good men against all the wicked, than with many wicked men against a few good men."
Both quotes are mentioned in the book Lives and Opinions of the Eminent Philosophers, by Diogenes Laertius.