Mark 8 is the center of the Second Gospel, both mathematically (16 total chapters) and thematically. Mark is built around the structure of confessing who Jesus is: the Messiah, the Son of God (1:1), the Messiah (8:29), and the Son of God (15:39).
Mark carefully constructs his Gospel to highlight this central confession by including a unique story of healing a blind man. This is the only occasion where Jesus performs a “two-stage” healing; the man’s sight is partially restored at first, then perfectly restored at last. This man’s healing is intended to be a parable of what is happening to the disciples: their vision of who Jesus is has been blurry until now, but with Peter’s confession their sight clears and they accept that He not 0nly brings the Kingdom, but is Himself the King.
Their acceptance of Jesus’ identity as the promised King and Messiah doesn’t mean they understand everything, however. Jesus moves on to the next phase of their education: He tells them openly that He as Messiah must be rejected, killed, and raised. Peter in his ignorance rebukes Jesus, who rebukes Peter’s rebuke just as forcefully. The Messiah’s path is necessarily the path of suffering and death, because it is necessarily the path of resurrection.
Notes and audio are available here.