A Rejected Christ

In verse 18, the Lord asks His disciples what it had all come to—"Whom say the people that I am?" They answer, "John the Baptist; but some say, Elias; and others say, that one of the old prophets is risen again." It had all come to nothing. "But whom say ye that I am? Peter answering said, The Christ of God. And He straightly charged them, and commanded them to tell no man that thing." Why? Because it was of no use. "The Messiah" had been rejected, and now He speaks of Himself, not as the Christ, or Messiah, but as the Son of man. This wider title characterizes the remaining chapters of this Gospel.
You will see a similar transition between the second Psalm and the eighth. In the second Psalm the Lord is spoken of as the Christ, or "Anointed," but in the eighth Psalm He is spoken of as "son of man." All things were once put in subjection to Adam and his wife but they lost this headship through sin. Now the Lord Jesus, the Son of man, will not take the inheritance of all things simply as Heir, but as Redeemer Heir. He has a personal right to it, true, but could He take it polluted with sin as it is, apart from redemption as well?
He never speaks of His sufferings as Son of man without speaking of His rising again. It is as the risen Son of man that He takes the headship of creation and all things as we see in Heb. 2.
In this passage, Luke 9, the Lord speaks of His sufferings as a martyr under man's hand, not as a victim under the hand of God for sin. His death had this double aspect-He suffered as a victim and as a martyr. As a martyr we can have the fellowship of His sufferings. He tells His disciples then of the path of those who would follow Him in His rejection, but He does not speak of the path without showing what the end of it will be.
Would you mind a rough, thorny path if you knew surely what the end would be? Here is the journey and the end of it. So Paul's desire was that he might apprehend that for which he was apprehended of Christ Jesus.