“Life After Hate groups have successfully reversed the hatred of thousands and replaced it with empathy, love, and self-forgiveness. If the haters can learn empathy, maybe we can learn empathy toward the haters. When our only response to haters is to hate, we increase our brain’s training to hate and decrease its training to empathize. We become a bit of the enemy we hate.”

1950s, Loving Your Enemies (November 1957)
Variant: Hate destroys the very structure of the personality of the hater.
Context: There’s another reason why you should love your enemies, and that is because hate distorts the personality of the hater. We usually think of what hate does for the individual hated or the individuals hated or the groups hated. But it is even more tragic, it is even more ruinous and injurious to the individual who hates. You just begin hating somebody, and you will begin to do irrational things. You can’t see straight when you hate. You can’t walk straight when you hate. You can’t stand upright. Your vision is distorted. There is nothing more tragic than to see an individual whose heart is filled with hate. He comes to the point that he becomes a pathological case. For the person who hates, you can stand up and see a person and that person can be beautiful, and you will call them ugly. For the person who hates, the beautiful becomes ugly and the ugly becomes beautiful. For the person who hates, the good becomes bad and the bad becomes good. For the person who hates, the true becomes false and the false becomes true. That’s what hate does. You can’t see right. The symbol of objectivity is lost. Hate destroys the very structure of the personality of the hater. [... ] when you start hating anybody, it destroys the very center of your creative response to life and the universe; so love everybody. Hate at any point is a cancer that gnaws away at the very vital center of your life and your existence. It is like eroding acid that eats away the best and the objective center of your life. So Jesus says love, because hate destroys the hater as well as the hated.

Source: Liar's Game

1950s, Loving Your Enemies (November 1957)
Context: There’s another reason why you should love your enemies, and that is because hate distorts the personality of the hater. We usually think of what hate does for the individual hated or the individuals hated or the groups hated. But it is even more tragic, it is even more ruinous and injurious to the individual who hates. You just begin hating somebody, and you will begin to do irrational things. You can’t see straight when you hate. You can’t walk straight when you hate. You can’t stand upright. Your vision is distorted. There is nothing more tragic than to see an individual whose heart is filled with hate. He comes to the point that he becomes a pathological case. For the person who hates, you can stand up and see a person and that person can be beautiful, and you will call them ugly. For the person who hates, the beautiful becomes ugly and the ugly becomes beautiful. For the person who hates, the good becomes bad and the bad becomes good. For the person who hates, the true becomes false and the false becomes true. That’s what hate does. You can’t see right. The symbol of objectivity is lost. Hate destroys the very structure of the personality of the hater. [... ] when you start hating anybody, it destroys the very center of your creative response to life and the universe; so love everybody. Hate at any point is a cancer that gnaws away at the very vital center of your life and your existence. It is like eroding acid that eats away the best and the objective center of your life. So Jesus says love, because hate destroys the hater as well as the hated.

As quoted in Understanding Cultural Diversity in Today's Complex World‎ (2006) by Leo Parvis, p. 54

Source: Locksley Hall Sixty Years After (1886), Line 85

Source: How I Grew (1987), Ch. 4

Quoted in Linda O. McMurray, George Washington Carver: Scientist and Symbol (Oxford University Press, 1982), p. 107

2000s, Where the Right Went Wrong (2004)

Source: The Fire Next Time