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. (1929–1968) American clergyman, civil rights leader, social activist, preacher

Strength To Love, ch. 5 “Loving Your Enemies,” sec. 2 (1963)
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