14 At the foot of the mountain, a large crowd was waiting for them. A man came and knelt before Jesus and said, 15 "Lord, have mercy on my son. He has seizures and suffers terribly. He often falls into the fire or into the water. 16 So I brought him to your disciples, but they couldn't heal him." 17 Jesus said, "You faithless and corrupt people! How long must I be with you? How long must I put up with you? Bring the boy here to me." 18 Then Jesus rebuked the demon in the boy, and it left him. From that moment the boy was well. 19 Afterward the disciples asked Jesus privately, "Why couldn't we cast out that demon?" 20 "You don't have enough faith," Jesus told them. "I tell you the truth, if you had faith even as small as a mustard seed, you could say to this mountain, 'Move from here to there,' and it would move. Nothing would be impossible. "
Matthew Henry's Commentary on Matthew 17:14-20
Commentary on Matthew 17:14-21
(Read Matthew 17:14-21)
The case of afflicted children should be presented to God by faithful and fervent prayer. Christ cured the child. Though the people were perverse, and Christ was provoked, yet care was taken of the child. When all other helps and succours fail, we are welcome to Christ, may trust in him, and in his power and goodness. See here an emblem of Christ's undertaking as our Redeemer. It encourages parents to bring children to Christ, whose souls are under Satan's power; he is able to heal them, and as willing as he is able. Not only bring them to Christ by prayer, but bring them to the word of Christ; to means by which Satan's strong-holds in the soul are beaten down. It is good for us to distrust ourselves and our own strength; but it is displeasing to Christ when we distrust any power derived from him, or granted by him. There was also something in the malady which rendered the cure difficult. The extraordinary power of Satan must not discourage our faith, but quicken us to more earnestness in praying to God for the increase of it. Do we wonder to see Satan's bodily possession of this young man from a child, when we see his spiritual possession of every son of Adam from the fall!