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.

Ender Wiggin must believe that no matter what happens, no adult will ever, ever step in to help him in any way.

Parents always make their worst mistakes with their oldest children. That's when parents know the least and care the most, so they're more likely to be wrong and also more likely to insist that they're right.

You who speak languages, you are such liars.

There was no name for the disease; his body had gone insane, forgotten the blueprint by which human beings were built. Even now the disease still lives on in his children. Not in our bodies, but in our souls. We exist where normal human children are expected to be; we're even shaped the same. But each of us in our own way has been replaced by an imitation child, shaped out of a twisted, fetid, lipidous goiter that grew out of Father's soul.

Everyone dies. Everyone leaves. What matters is the things you build together before they go. What matters is the part of them that continues in you when they're gone.

If anyone have intercourse with a pig or a dog, he shall die. If a man have intercourse with a horse or a mule, there is no punishment. But he shall not approach the king, and shall not become a priest... If a pig spring upon a man for intercourse, there is no punishment.