17:14–15 When they came to the crowd, a man came to him, knelt before him, and said, “Lord, have mercy on my son, for he is an epileptic and he suffers terribly; he often falls into the fire and often into the water.” ^N Jesus, Peter, James, and John came down from the mountain and returned to the other nine disciples (Luke 9:37 says this occurred “the next day”), who apparently were with a crowd. Mark explains that a crowd surrounded the disciples and some teachers of the law who were in a heated argument. The nature of the argument is not stated, but we can assume that the religious leaders were arguing with the disciples about their power and authority or about the power and authority of their Master, because the disciples had tried and failed to cast out a demon (17:16).

A man came from the crowd and knelt before Jesus. Respectfully calling Jesus Lord, he asked for mercy on his son, who was an epileptic. Mark gives more detail, for the man explained that he had come looking for Jesus to heal his son who was possessed by an evil spirit, making him unable to utter any sound (also he could not hear, see Mark 9:25). This was not just a case of epilepsy; it was the work of an evil spirit. The demon’s destructive intent is seen in that the boy would often fall into the fire or water.

17:16       “So I brought him to Your disciples, but they could not cure him.”  Having heard of Jesus’ power to cast out demons, the father had come to Jesus, hoping for a cure for his son. He brought his son to the disciples to drive out the spirit, an appropriate request since the disciples had been given this power (10:1). The disciples could not drive out the demon, however, even though they had been given power to do so (10:8). Matthew records the failure of the disciples throughout this section (14:16–21, 26–27, 28–31; 15:16, 23, 33; 16:5, 22; 17:4, 10–22). It serves to teach that the power to heal is God’s, not ours. We must appropriate it by faith.

17:17–18 “O unbelieving and perverse generation,”Jesus replied, “how long shall I stay with you? How long shall I put up with you?”  Jesus cried out in exasperation, fed up with unbelief and lack of faith. His unusual words carry a biting rebuke. They parallel Moses’ frustration as intercessor for God’s people (Deuteronomy 32:5, 20) and portray God’s frustration with his people (Numbers 14:11; Isaiah 63:8–10). The disciples had been given the authority to do the healing, but they had not yet learned how to appropriate God’s power. Jesus’ frustration was with the unbelieving and unresponsive generation, including the crowd, the teachers of the law (scribes), the man, and the nine disciples. His disciples merely reflected that attitude of unbelief so prevalent in the society.

 “Bring him here to me.” And Jesus rebuked the demon, and it came out of him, and the boy was cured instantly.  Jesus rebuked the demon, and it came out of the boy (Mark’s Gospel describes how the demon convulsed the boy terribly one last time before leaving, Mark 9:26). Demons are never pleased to be told to leave their human dwellings, yet they have no choice but to submit to the higher authority. As always when Jesus healed, the cure was complete.

17:19–20 Then the disciples came to Jesus in private and asked, “Why couldn’t we drive it out?” He replied, “Because you have so little faith.”  The disciples had been unable to drive out this demon, and they asked Jesus why. They had cast out demons before; why hadn’t this demon responded? Jesus pointed to their lack of faith. Perhaps the disciples had tried to drive out the demon with their own ability rather than God’s. If so, their hearts and minds were not in tune with God, so their words had no power. Their question revealed their error; they centered on themselves (we), not on Christ.

 “I tell you the truth, if you have faith as small as a mustard seed, you can say to this mountain, ‘Move from here to there’ and it will move. Nothing will be impossible for you.”  Jesus pointed to the disciples’ lack of faith. Jesus wasn’t condemning the disciples for substandard faith; he was trying to show how important faith would be in their future ministry. It is the power of God, not our faith, that moves mountains, but faith must be present to do so. The mustard seed was the smallest seed known. But like the mustard seed that grew into a large garden plant (13:31–32), even a small “seed” of faith is sufficient. There is great power in even a little faith when God is with us. If we feel weak or powerless as Christians, we should examine our faith, making sure we are trusting not in our own abilities to produce results but in God’s. If we are facing problems that seem as big and immovable as mountains, we must turn our eyes from the mountain and look to Christ for more faith. Then, as Jesus promised, nothing will be impossible. It is not the “amount” of faith that matters; rather, it is the power of God available to anyone with even the smallest faith. We cannot fail when we have faith.

Obedience is the one sure characteristic of the surrender of faith. Faith that is not coupled with obedience is a pretense.  Andrew Murray

17:21       “However, this kind does not go out except by prayer and fasting.”  This verse does not appear in most modern translations because the best Greek manuscripts do not have it. However, it does occur in Mark 9:29, although the best manuscripts there do not have “and fasting.” Jesus explained that this kind [of demon] does not go out except by prayer and fasting and that the disciples had not depended on God’s power through prayer. God’s power must be requested and relied upon in each instance.

Prayer is the key that unlocks and reveals faith. Effective prayer needs both an attitude of complete dependence and the action of asking. Prayer demonstrates complete reliance on God. It takes our mind off ourselves and focuses it totally on God. This helps us deal with difficult situations.^[1]

^[1] Bruce B. Barton, Matthew, Life Application Bible Commentary (Wheaton, IL: Tyndale House Publishers, 1996), 345–347.