What does Matthew 17:17 mean?

While Jesus was away on the mountain with Peter, James, and John (Matthew 17:1–13), a desperate father brought his demon-afflicted son to Jesus' remaining nine disciples (Matthew 10:1–4). The demon has caused the boy to be mute and experience epileptic-style seizures. Partly proving that this is not simple epilepsy is how often the boy is thrown "into fire and into water, to destroy him" (Mark 9:22).

The disciples attempted to cast the demon from the boy, but they were unable. This provoked an argument with some Jewish scribes, perhaps about whether the disciples had the authority to cast out demons. This was something most scribes did not even claim for themselves. Though the disciples were not rabbis or official Jewish leaders, they did have the authority to cast out demons. Jesus had specifically given them the power to represent Him in this specific way (Matthew 10:8).

Jesus sounds exasperated both with His disciples and His people. He lumps them in together as a "faithless and twisted" generation. Mark's account of this story shows that the faith of the father is also an issue in this healing (Mark 9:22–24). His comments here are the first suggestion we see in Matthew's writing of Jesus growing weary of His time among humanity. When Jesus expresses this kind of frustration, the issue is nearly always the same: unbelief. Specifically, the people of "this generation" have failed to believe in Him as the Messiah and in His authority and power as the Son of God.

Jesus asks the father to bring his demon-afflicted son to Him.