Alexander Solzhenistsyn was once a Russian officer who was arbitrarily arrested and spent many years in the gulags. He had gone in as a convinced Bolshevik, he emerged as a convinced Christian.
Subsequently he won a Nobel prize for Literature and was very popular in the U.S., partly because he said things that fit our political inclinations. When he criticized some aspects of American life, he became less popular and his book about Jews and Russia (200 Years Together) was apparently thought so dangerous that it has been suppressed. Incredibly, in the land of free speech, it is not available in English!
The gulags provided a good laboratory for the study of human good and evil, and his cancer provided time for self-reflection. Here are his thoughts:
It was granted to me to carry away from my prison years on my bent back, which nearly broke beneath its load, this essential experience: how a human being becomes evil and how good.
In the intoxication of youthful successes I had felt myself to be infallible, and I was therefore cruel. In the surfeit of power I was a murderer and an oppressor. In my most evil moments I was convinced that I was doing good, and I was well supplied with systematic arguments.
It was only when I lay there on rotting prison straw that I sensed within myself the first stirrings of good. Gradually it was disclosed to me that the line separating good and evil passes not through states, nor between classes, nor between political parties either, but right through every human heart, and through all human hearts.
Since then I have come to understand the truth of all the religions of the world: they struggle with the evil inside a human being (inside every human being). It is impossible to expel evil from the world in its entirety, but it is possible to constrict it within each person.