“Never tell your enemy he is doing the wrong thing.”

“There are more pleasent things to do than beat up people. Forgive your enemies, but never forget their names.”

“An enemy, Ender Wiggin," whispered the old man. "I am your enemy, the first one you've ever had who was smarter than you. There is no teacher but the enemy. No one but the enemy will tell you what the enemy is going to do. No one but the enemy will ever teach you how to destroy and conquer. Only the enemy shows you where you are weak. Only the enemy tells you where he is strong. And the rules of the game are what you can do to him and what you can stop him from doing to you. I am your enemy from now on. From now on I am your teacher.”

“No captain can do very wrong if he places his ship alongside that of the enemy.”

“There may be a wrong way to do the right thing, but never a right way to do a wrong thing.”

“But the only way never to do the wrong thing is never to do anything.”