It was like a mask had been pulled away from his face, uncovering a monster hidden beneath his friendly façade.

Mark nodded even though she couldn't see. He'd suddenly lost any desire to talk, and his plans for a perfect day washed away with the stream. The memories. They never let him go, not even for a half hour. They always had to rush back in, bringing all the horror.

Every danger loses some of its terror once its causes are understood.

When the devil wants to punish his worshippers, he uses the trick of karma.

Now that little problem of yours, this business of not knowing good men from bad men and villains from heroes and so forth...There's still plenty for you to do. And you'll do it. And when you fall in love and have a mistress or a wife and children to look after, it will all seem easier." He opened the door but stopped on the threshold. "Surround yourself with human beings, my dear. They are easier to fight for than principles." He laughed. "But don't let me down and become human yourself. We would lose such a wonderful machine." With a wave of his hand he shut the door.

There's a Good Book about goodness and how to be good and so forth, but there's no Evil Book about how to be evil and how to be bad. The Devil had no prophets to write his Ten Commandments, and no team of authors to write his biography. His case has gone completely by default. We know nothing about him but a lot of fairy stories from our parents and schoolmasters. He has no book from which we can learn the nature of evil in all its forms, with parables about evil people, proverbs about evil people, folklore about evil people. All we have is the living example of people who are least good, or our own intuition.