If I solve my dispute with my neighbor by killing him, I have certainly solved the immediate dispute. If my neighbor was a scoundrel, then the world is no doubt better for his absence. But in killing my neighbor, though he may have been a terrible man who did not deserve to live, I have made myself a killer — and the life of my next neighbor is in greater peril than the life of the last.

Wendell Berry (b. 1934) American farmer, educator, poet, conservationist

Speech (1968-02-10), “A Statement Against the War in Vietnam,” Kentucky Conference on the War and the Draft, University of Kentucky
    (Source)

Collected in The Long-Legged House, Part 2 (1969).