What are the motifs in Cash: The Autobiography by Johnny Cash?

Love of God is a recurring idea. There is a low point in Johnny's life in which he goes to a labyrinth of caves and crawls inside with the intention of dying there. He says that when his flashlight goes out, he lies in the dark and is very still. It's there that he realizes that God has a purpose for his life and that it's not up to him to decide when his life will end. Johnny manages to find his way out of the caves and finds June and his mother waiting for him. He immediately tells them that he's dedicating his life to God and will do whatever it takes to make that happen.