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. Even within hearts overwhelmed by evil, one small bridgehead of good is retained; and even in the best of all hearts, there remains a small corner of evil. It is impossible to expel evil from the world in its entirety, but it is possible to constrict it within each person.
– Aleksandr Solzhenitsyn
Source: The Gulag Archipelago