Look at what Aleksandr Solzhenitsyn wrote in The Gulag Archipelago about good and evil.
For a good person even a crust is healthy food, and to an evil person even meat brings no benefit.
The Gulag Archipelago, Volume 2, p 610
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. This line shifts. Inside us, it oscillates with the years. And even within hearts overwhelmed by evil, one small bridgehead of good is retained. And even in the best of all hearts there remains … an unuprooted small corner of evil.
The Gulag Archipelago, Volume 2, p 615