Our life is shaped by our mind; we become what we think. Joy follows a pure thought like a shadow that never leaves.
"He was angry with me, he attacked me, he defeated me, he robbed me" -- those who dwell on such thoughts will never be free from hatred.
"He was angry with me, he attacked me, he defeated me, he robbed me" -- those who do not dwell on such thoughts will surely become free from hatred.
For hatred can never put an end to hatred; love alone can. This is an unalterable law. People forget that their lives will end soon. For those who remember, quarrels come to an end.
--- from The Dhammapadda, tr. Eknath Easwaran