While they abode ( ἀναστρεφομε ìνων, went to and fro; conversantibus, Vulgate) in Galilee. After some weeks spent in the extreme north, Jesus and his disciples had returned secretly to Galilee (Mark 9:30), and were approaching the neighborhood of Capernaum.
The privacy was connected with the special instruction which he was now giving to his disciples. The Son of man shall be betrayed … men. There is a reference to the preparation thus mercifully afforded to the twelve in the angel's address to the women at the sepulchre, "Remember how he spake unto you when he was yet in Galilee" (Luke 24:6).
Jesus reiterates the prediction continually in order to familiarize his followers with the unwelcome, the incredible, reality. But the Messiah's Passion, death, and resurrection were ideas that they could not at once receive; so impossible they seemed in the very nature of things, so contrary to all their hopes and expectations.
Shall be betrayed ( με ìλλει παραδιδοσθαι). Is ordained, in the counsels of God, to be betrayed. Tradendus est (Vulgate). Men. He had before named the chief priests (Matthew 16:21), afterwards he mentions the Gentiles (Matthew 20:19), as the agents in his death.
So St. Peter, in his great sermon (Acts 2:1-47), says to the Jews, "Ye have taken him, and by wicked hands ['by the hand of lawless men,' Revised Version] have crucified and slain."