“If you refrain from judging your worst enemy, his children will come to your side. What more severe judgment could come upon an enemy than this?”

“The greater your successes and victories, the more opposition your enemies will come your way, with painful and discouraging events.”

“Never hate your enemies. It affects your judgment.”

“Your worst enemy cannot harm you as much as your own unguarded thoughts.”

“If you can't make yourself understood by your friends, you'll be in trouble when your enemies come for you.”

““What more could you need?”
I smiled in self-mockery. “Reassurance, I suppose.”
“That must come from your own judgment, from your own testing of your conscience. It is the only kind of reassurance worth having, as I’m sure you would agree.””

“If you are your own worst enemy, don't do yourself any favors.”

“By the time you're thirty, your worst enemy is yourself.”

“Extremes are ultimately their own side's worst enemy.”

“A blow from your friend is better than a kiss from your enemy.”