A good quote

Don't normally comment on religion, apart from my little fishing related conversations with God, but this verse caught my eye. Which holy text is this quotation from?

Good and evil are not equal. Repel evil with what is best in goodness, and you will see that the one you had mutual enmity with, will turn around as if he were a close friend.

Not always true when you're dealing with psycho's and frothing at the brain madmen, but it works for most ordinary people. Pity it's so often hard to tell the difference.