Luke separates the ministry of John the Baptist from the ministry of Jesus by reporting the imprisonment of John before the baptism of Jesus (Luke 3:21-22). Luke does this to separate the distinct periods of salvation history. With John the Baptist, the time of promise, the period of Israel, comes to an end; with the baptism of Jesus and the descent of the Spirit upon him, the time of fulfillment, the period of Jesus, begins. The world has finally, without doubt, introduced to the Son of God, that has come to change, to save, the world!