“And when they came to the disciples, they saw a great crowd around them, and scribes arguing with them. And immediately all the crowd, when they saw him, were greatly amazed and ran up to him and greeted him. And he asked them, ‘What are you arguing about with them?’ And someone from the crowd answered him, ‘Teacher, I brought my son to you, for he has a spirit that makes him mute. And whenever it seizes him, it throws him down, and he foams and grinds his teeth and becomes rigid. So I asked your disciples to cast it out, and they were not able.’ … And Jesus asked his father, ‘How long has this been happening to him?’ And he said, ‘From childhood. 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.’ And Jesus said to him, ‘‘If you can’! All things are possible for one who believes.’ Immediately the father of the child cried out and said, ‘I believe; help my unbelief!’ And when Jesus saw that a crowd came running together, he rebuked the unclean spirit, saying to it, ‘You mute and deaf spirit, I command you, come out of him and never enter him again.’ And after crying out and convulsing him terribly, it came out, and the boy was like a corpse, so that most of them said, ‘He is dead.’ But Jesus took him by the hand and lifted him up, and he arose. And when he had entered the house, his disciples asked him privately, ‘Why could we not cast it out?’ And he said to them, ‘This kind cannot be driven out by anything but prayer.'” (Mark 9:14-29)
“This kind cannot be driven out by anything but prayer” means that there are no magic Jesus powers. His healing ministry was not from His own power. He was not a magician. Contrary to popular misconceptions that assume that Jesus came to earth as some sort of Superhuman, Mark finds it very important to show us that Jesus’s miraculous exploits were the product of His being in step with the Holy Spirit through prayer. It is essential to historic Christian theology that when God the Son came to earth, He did so without any special advantages. He was a regular Jew with a 9 to 5 and a mom. All of the miraculous feats He performed, all of the counter-cultural teaching that He espoused, His supernatural compassion and concern for the outcast, His boldness, were all the product of His submission to and communion with God the Spirit, who indwelt Him.
This is important to grasp, in no small part because it clears the confusion that Jesus stirs up when He says to the original gathered Church, “Very truly I tell you, whoever believes in me will do the works I have been doing, and they will do even greater things than these, because I am going to the Father.” (John 14:12) He really meant that we would do more than He did, not because we would be more powerful, but because as the Church multiplies and lost sinners are transformed into Spirit-filled believers, the ministry of Jesus itself multiplies and expands. Before His crucifixion, there was one Jesus who made disciples and incarnated the kingdom of God in the midst of a broken world. Today, 2000 years after His resurrection, it is as though there are approximately 2.2 billion Jesuses walking the earth.
“This kind cannot be driven out by anything but prayer” also means that our ability to do anything spiritual, be it cast out demons (yeah, that actually happens), win souls for Christ, or overcome the darkness in us, comes from helpless dependence on God. We are not prayer warriors; the Holy Spirit is a prayer warrior. When we pray for ourselves, whether it’s for a greater love for the Father, a greater freedom from sin, a more obedient heart, etc., we are echoing the Holy Spirit’s earnest prayers on our behalf (Rom. 8:23, 26-27). Jesus walked in utter dependence on the Holy Spirit’s guidance as an incarnated human. We are no less dependent now that He indwells us. Every Christian believes in the Holy Spirit, but ‘believing’ in Him in any meaningful sense means living in a ‘dethroning’ submission to His lead. The person who believes in the Holy Spirit is always in prayer to seek His guidance. She is always communing with Him in prayer to know the Father more intimately. She is always laying down what remains of her stubborn will in prayer to let Him mold her into the image of Christ.
“This kind cannot be driven out by anything but prayer” because we can only “do greater things than these” as people who are pathetic, weak, and like Jesus, are desperately dependent on the Spirit of God to enable us to find and carry out the will of God.