Lk 9:43b-45
43While [the crowd and the disciples] were all amazed at his every deed, [Jesus] said to his disciples, 44“Pay attention to what I am telling you. The Son of Man is to be handed over to men.” 45But they did not understand this saying; its meaning was hidden from them so that they should not understand it, and they were afraid to ask him about this saying.
Son of Man: The form is frequently used in the book of Ezekiel as God’s address to the prophet and must mean simply “O man”: “Son of man, stand up! I wish to speak with you” (Ez 2:1). The Aramaic form bar nasa is used in Dn 7:13 to designate one “like a son of man” who appears on the clouds before the Ancient of Days and receives a kingdom. This figure symbolizes Israel (Dn 7:18, 22) who is persecuted but who will receive his reward from God. The title appears in the apocryphal books of Enoch and Esdras where the son of man is presented as the righteous one who reveals all hidden treasures, overcomes kings and powerful ones, and sits on the throne with the power to judge.
In the New Testament, the phrase does not appear in the epistles, and in the gospels, it is used only by Jesus. To scholars this suggests that the title was original with Jesus, but was not used later by the Church.
The phrase is used in the gospels with various associations and meanings. The Gospel reading belongs to numerous groups of texts which speak of the passion and death of the Son of Man. It is precisely as Son of Man that Jesus suffers and dies. It is Jesus’ humanity that makes him capable of suffering, and thus it is under this title that he experiences his passion.
But Jesus will rise again and will someday return in glory. And so, as the Son of Man, he will come in glory at the end of time. This apocalyptic-eschatological coming is obviously derived from the “Son of Man” from Daniel. The glorious fate of Israel is embodied in the person and destiny of Jesus.