And He began to teach them that the Son of Man must suffer many things and be rejected by the elders and the chief priests and the scribes and be killed, and after three days rise again (Mark 8.31).
The center of Mark’s Gospel is the cross of Christ. Once the Twelve had grasped who Jesus was and had confessed Him as the Messiah, He began to teach them about the cross. It was a turning point in Jesus’ ministry and so also in Mark’s gospel.
The essence of Jesus’ teaching is found in His statement the Son of Man must suffer. Why must He suffer? What is the origin of His sense of compulsion? It is because the Scriptures must be fulfilled. Why, then, the Son of Man? By using this Hebraism for a human being, Jesus was referring to Daniel 7. In that vision “one like a son of man” (that is, a human being) comes on the clouds and approaches the Ancient of Days (God). He was then given authority and sovereign power so that all people will serve Him, and His kingdom will never be destroyed (Daniel 7.13-14).
Jesus adopted the title Son of Man but changed his role. According to Daniel, all nations would serve him. According to Jesus, He had come to serve, not to be served. In fact, Jesus did what nobody else had done: He fused the two Old Testament images, Isaiah’s servant who suffers and Daniel’s Son of Man who reigns. For first Jesus must bear our sins and only then rise and enter His glory.
– John Stott, Through the Bible, Through the Year