Astonishing Greatness

Jesus comes down off the Mountain - after his transcendent glory is revealed in the Transfiguration - and Luke (like the other Synoptics) follows this event with the casting out of a demon from a young boy. The father of this son brings him to Jesus because the evil spirit has long plagued him and done much harm to him. He says that he first brought his son to the disciples, but Luke informs us that the disciples were unable to cast out the demon. This is interesting because Jesus gave his disciples authority and power to preach, heal, and cast out demons at the outset of chapter 9. 

Jesus responds to this by lamenting the disbelief of this present generation. It is unclear whether this is specifically directed towards the disciples or if this is a general remark towards the crowd. While Jesus is moved by compassion to heal this boy, Luke seems to include this event here in his account in order to demonstrate Jesus' set apart, preeminent power. While Mark will include a statement on why the disciples cannot perform this act, Luke is unconcerened with the reason. Instead, he is content to make it clear that Jesus can and does where the disciples couldn't and didn't. Luke informed us that Christ would be delivered over to suffer and die, then he gave us an incredible display of Christ's glory. Now, he again gives us a remarkable demonstration of Jesus' power (over the spirits afflicting men and beyond the ability of men to deliver themselves). And concludes with another reminder that the Son of Man will soon be delivered into the hands of men to suffer and die.