Mark 9:22 (ESV) … “And it has often cast him into fire and into water, to destroy him. But if you can do anything, have compassion on us and help us.”
In the passage above, a demon has responded violently when it saw Jesus. This passage is reminiscent of Mark 5:6. Jesus’ questioning of the father was meant to bring a confession of need. It may seem a strange question. Why would the father not admit his need in verse 21? And yet, many parents are blinded to disabilities.
Psychologist John White admitted that when his son was born with a club foot, he literally did not see it. Denial can be a strong opponent—perhaps the only thing that can forever block Jesus’ healing touch. The Master forced the father to acknowledge that Jesus was his only hope. While the man knew this, he did not know whether this hope was enough. After all, the disciples had been unable to do anything for the son. Perhaps this had shaken his faith somewhat.
Jesus declared that he had the power to heal his son if the man had the faith. If you can?… Everything is possible for him who believes, he declared. Jesus did not mean that miracles depend on the strength of a person’s faith. We must pray always with God’s will in mind. The father confessed his belief immediately. It sprang from his heart. But he was aware that he was an imperfect human being; his recent lack of faith proved it.
Therefore, he asked Jesus to heal him—the father—first. “Whatever is in me, Lord, that does not believe or want to believe, heal that first.” Like removing the log from our own eye, this request was not only appropriate but life-giving. 
With Jesus, all things are possible. One who could create a hundred billion galaxies, each composed of a hundred billion stars, was not to be daunted by the antics of a demon.