Hate cannot drive out hate...

"Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that. Hate multiplies hate, violence multiplies violence, and toughness multiplies toughness in a descending spiral of destruction....The chain reaction of evil--hate begetting hate, wars producing more wars--must be broken, or we shall be plunged into the dark abyss of annihilation."

Martin Luther King, Jr., Strength To Love, 1963.
Source: http://www.mlkonline.net/quotes.html