“Evil is not any superhuman, but it is HUMAN.”

“Evil is not something superhuman, it's something less than human.”

“Nowadays, no one believes in evil. It is considered, at most, a mere negation of good. Evil, people say, is done by those who know no better - who are undeveloped - who are to be pitied rather than blamed. But, M. Poirot, evil is real! It is a fact! I believe in Evil as I believe in Good. It exists! It is powerful! It walks the earth!' He stopped. His breath was coming fast. He wiped his forehead with his handkerchief and looked suddenly apologetic. 'I'm sorry. I got carried away.”

“Evil never goes unpunished, Monsieur. But the punishment is sometimes secret.”

“One does see so much evil in a village,' murmured Miss Marple in an explanatory voice.”

“Elephants can remember, but we are human beings and mercifully human beings can forget.”

“I know there's a proverb which that says 'To err is human,' but a human error is nothing to what a computer can do if it tries.”