He said after a little while, 'I see why you say that only men do evil, I think. Even sharks are innocent, they kill because they must.' 'That is why nothing can resist us. Only one thing in the worl can resist an evil-hearted man. And that is another man. In our shame is our glory. Only our spirit, which is capable of evil, is capable of overcoming it.
Ursula K. Le Guin, The Farthest Shore
wisdom