In context of the passage what is the meaning of 'conflict'?

Directions: Read the following passage and answer the questions.

Graham Greene was one of the most outstanding novelists after the Second World War. His remarkable novels are mainly concerned with evil and its endless conflict with righteousness. He saw action as a series of moral dilemmas and he depicts fundamental good and fundamental evil. His famous novels are Power and the Glory, The End of the Affair, Brighton Rock.