In Mark 9, why weren't the disciples able to heal the demon possessed boy? Why did they still need Jesus’ intervention?
Peter, James, and John have been with Jesus on the mountain and seen Him “transfigured before them” (v. 2). They have heard God say, “This is my Son whom I love” (v. 7). As these disciples descend the mountain with Christ, they find the other nine in a dilemma: A large crowd surrounds a demon-possessed boy and his father, and the nine are unable upon the father’s request to “drive out the spirit” (v. 18). Christ had given them the authority to cast out demons (Mark 6:7, 13). These were men who had walked and talked with Christ on a daily basis. But something was amiss. Clearly dismayed, Jesus says, “O unbelieving generation, how long shall I stay with you? How long shall I put up with you? Bring the boy to me” (v. 19).
This is, as one commentator puts it, “a cry wrung from the heart of Jesus. He staked His life on the redemption of the world, only to find His nearest followers, His chosen men, beaten and baffled, helpless, and ineffective.” After Jesus delivers the boy from the demon, the disciples ask Him why they couldn’t do it. Note Jesus’ answer: He says that they could only do it “by prayer” (v. 29).
Christ’s words tell us a great deal. Faith must be maintained by prayer if it is to overcome the enemy. One cannot become careless in his or her walk with God. The disciples simply could not do the work of the Lord unless they were constantly dependent upon Him. In effect, Christ was saying to them, “You don’t live close enough to God.” They had been given power, but they needed prayer to maintain it. Unless we also stay close to God, we lose our vitality and the humility of dependence.