Invite your friend to dinner; have nothing to do with your enemy.

...Perses, hear me out on justice, and take what I have to say to heart; cease thinking of violence. For the son of Kronos, Zeus, has ordained this law to men: that fishes and wild beasts and winged birds should devour one another, since there is no justice in them; but to mankind he gave justice which proves for the best.

He is senseless who would match himself against a stronger man; for he is deprived of victory and adds suffering to disgrace.

Do not seek dishonest gains: dishonest gains are losses.

For both faith and want of faith have destroyed men alike.

But they who give straight judgements to strangers and to those of the land and do not transgress what is just, for them the city flourishes and its people prosper.

An evil plan does mischief to the planner.