What does Luke 21:38 mean?

Since the arrest of John the Baptist, Jesus has taught and ministered publicly. The Jews and their religious leaders have had about three years to hear Him and determine if His teaching is true. In the week beginning with His triumphal entry, Jesus has kept a regular schedule of sleeping on the Mount of Olives at night and teaching in the temple Court during the day. The people learned to expect Him and greeted Him every morning.

Luke records relatively little of what Jesus taught in this week. Luke 20 records how He defended His heavenly authority against the religious and civil leaders who felt threatened by His popularity. Mark and Matthew include a discussion on the Great Commandment (Mark 12:28–34; Matthew 22:34–40). Matthew also includes the parables of the two sons and the wedding feast, and an extensive, detailed description of the sins of the scribes and Pharisees (Matthew 21:28–32; 22:1–14; 23:1–36). John gives unique teachings about the purpose of Jesus' coming crucifixion and the disbelief of the people (John 12:27–50).

Beginning in this chapter, Jesus' teaching is confined to His followers. Luke 21:5–36 may have been given only to Peter, Andrew, James, and John (Mark 13:3). John gives an extended account of what Jesus taught in the upper room, including the High Priestly Prayer (John 13—17). After His resurrection, Jesus will explain to two disciples how the Old Testament prophesied the Messiah's death (Luke 24:25–27) as well as many things that aren't recorded (John 20:30–31).

Now, Luke has come to the Last Supper and the cross. Jesus' promises about the coming kingdom of God cannot come to fruition if He does not first die to cover the sins of the world.