“Personal affection is a luxury you can have only after all your enemies are eliminated. Until then, everyone you love is a hostage, sapping your courage and corrupting your judgment.”

“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.”

“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 only 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. I will devise the strategy of your army, and you will learn to be quick and discover what tricks the enemy has for you. Remember, boy. From now on the enemy is more clever than you. From now on the enemy is stronger than you. From now on you are always about to lose.”

“Home is anywhere that you know all your friends and all your enemies.”

“The only teacher that's worth anything to you is your enemy.”

“He loved her, as you can only love someone who is an echo of yourself at your time of deepest sorrow.”

“It's not enough just to laugh at good fortune and say, 'Enough already.' You have to really mean it -- that you have enough. And because you mean it, you take the surplus and you give it away. Similarly, when bad fortune comes, you bear it until it becomes unbearable -- your family is hungry, or you can no longer function in your work. And then again you say, 'Enough already,' and you change something. You move; you change careers; you let your spouse make all the decisions. Something. You don't endure the unendurable.”