What does Matthew 20:17 mean?

Matthew now reminds us that Jesus is continuing to move toward Jerusalem. He has left behind His life and ministry in the region of Galilee. In voluntarily moving toward Jerusalem, the seat of both Roman and Jewish power in Israel, Jesus has initiated the final steps toward the completion of His mission. This is more than a change of scenery; this also implies Jesus is heading towards His enemies, and eventual execution (Mark 8:31). For the third time, He will once again describe exactly what will happen to Him when they reach Jerusalem.

There can be no doubt. Jesus fully understood who He was and why He had come to earth in the first place. He was, in truth, "the Christ, the Son of the living God," just as Peter had described Him (Matthew 16:16). What that meant, though, Peter did not understand. Jesus had not come to overthrow and rule and judge on earth at this time. He had come to die, as the Son of God, for the sins of humanity and to be raised, by the power of God, from the dead. He had come to make a way out of sin and death once and for all.