When people speak badly of you, you should respond in this way: Keep a steady heart and don't reply with harsh words. Practice letting go of resentment and accepting that the other's hostility is the spur to your understanding. Be kind, adopt a generous stand-point, treat your enemy as a friend, and suffuse all your world with affectionate thoughts, far-reaching and widespread, limitless and free from hate. In this state you should try to remain.

-- The Buddha, Dhammapada