This is the first of three times Jesus told his disciples that he would suffer. He said he would be betrayed, crucified, and killed (see also Matthew 17:22–23; 20:18–19). Each of these predictions also taught a lesson about the cost of following him (see 16:24–27; 20:20–28).
The suffering of Jesus was part of God’s plan and was necessary for the Messiah (see 17:12).