The Failure Of The Disciples To Cast Out A Demon (17:14-18).
On arrival at the bottom of the mountain they came across a crowd of people who were with the disciples and there discovered that while Jesus was in the mountain they had been unable to heal a boy who gave the appearance of being epileptic as a result of the presence of a powerful demon active within him. Observing this Jesus expresses His concern at the faithlessness of that generation and heals the boy. This incident is always connected with the Transfiguration and it may well be that there is an indication in this that without the presence of Jesus with them the disciples' faith had been affected. They were not sure where He had gone or what He was doing. It may also indicate that with Jesus involved in heavenly activity and out of the way the demon world felt more assured.
But we should note that Matthew, unlike Mark, lays little stress on the demonic power at work here, although noting it at the end. He speaks rather of the boy being ‘cured'. There was seemingly a mixture of disease and demon possession. Perhaps indeed the demon possession had taken place as a result of using occult methods to try to cure the boy of epilepsy. Matthew's main aim here is to bring out the failure and lack of faith of the disciples. And as usual he abbreviates considerably.
A vivid picture is found here of how little the disciples could achieve without the power of Jesus with them. That is why Jesus' last words in Matthew are, ‘lo I am with you always' (Matthew 28:20). Without Him they could do nothing.
Analysis.
a And when they were come to the crowd, there came to him a man, kneeling to him (Matthew 17:14).
b Saying, “Lord, have mercy on my son, for he is epileptic, and suffers grievously, for regularly he falls into the fire, and regularly into the water” (Matthew 17:15).
c “And I brought him to your disciples, and they could not cure him” (Matthew 17:16).
d ‘And Jesus answered and said, “O faithless and perverse generation, how long shall I be with you? How long shall I bear with you?” (Matthew 17:17 a).
c “Bring him here to me” (Matthew 17:17 b).
b And Jesus rebuked him, and the demon went out of him (Matthew 17:18 a).
a And the boy was cured from that hour (Matthew 17:18 b).
Note that in ‘a' the man came to Jesus and knelt before Him, and in the parallel the boy was subsequently cured. In ‘b He learned about the demon's activity in the boy, and in the parallel He cast it out. In ‘c' the boy was brought to the disciples but they could not cure him, and in the parallel Jesus said ‘Bring him to Me'. Centrally in ‘d' Jesus bemoaned the faithlessness and perversity of that generation.