1. Jesus is the Messiah (18-22)
Jesus asked his disciples, "Who do the crowds say I am?" Popular opinion varied from John the Baptist to Elijah to a prophet of old. But there was a consensus that Jesus was someone from God. Then Jesus asked his disciples something we must all answer at some point, "Who do you say I am?" Peter answered, "God's Messiah." Contrary to the popular view, the Messiah would not be a political figure. The Messiah would suffer, be rejected, killed and then be raised to life. The Messiah would do this to save us from our sins.
2. To be a disciple of Jesus (23-27)
Discipleship requires self-denial, taking up one's cross and following Jesus every day. Jesus points out the foolishness of saving one's life and possibly even gaining the whole world and yet losing one's life in the end. If a person is ashamed of Jesus now, Jesus will be ashamed of him when he returns. However, everyone who loses their life for Jesus will save it for eternal life.