“Your enemies can kill you, but only your friends can hurt you.”
“Only a true best friend can protect you from your immortal enemies.”
“Your enemy is never a villain in his own eyes. Keep this in mind; it may offer a way to make him your friend. If not, you can kill him without hate — and quickly.”
“The enemies of your enemies are not always your friends, but they can still be useful.”
“You cannot be betrayed by your enemies, only your friends.”
“It takes your enemy and your friend, working together, to hurt you to the heart: the one to slander you and the other to get the news to you.”