Luke reintroduces us to John the Baptist who is now in prison. John hears the report of Jesus, but wonders if Jesus is the Messiah. This is a shockingly different attitude from the confident John we see in chapter 3. It is a section in which we see a genuine believer begin to doubt, but also what he does to remedy that doubt. There are important lessons for the Christain, but it's also another passage clearly revealing the truthfulness of Jesus' identity-- that He is God's true Messiah of salvation-