9:14 When they came to the disciples, they saw a large crowd around them and experts in the law arguing with them. 15 When the whole crowd saw him, they were amazed and ran at once and greeted him. 16 He asked them, “What are you arguing about with them?” 17 A member of the crowd said to him, “Teacher, I brought you my son, who is possessed by a spirit that makes him mute. 18 Whenever it seizes him, it throws him down, and he foams at the mouth, grinds his teeth, and becomes rigid. I asked your disciples to cast it out, but they were not able to do so.” 19 He answered them, “You unbelieving generation! How much longer must I be with you? How much longer must I endure you? Bring him to me.” 20 So they brought the boy to him. When the spirit saw him, it immediately threw the boy into a convulsion. He fell on the ground and rolled around, foaming at the mouth. 21 Jesus asked his father, “How long has this been happening to him?” And he said, “From childhood. 22 It has often thrown him into fire or water to destroy him. But if you are able to do anything, have compassion on us and help us.” 23 Then Jesus said to him, “‘If you are able?’ All things are possible for the one who believes.” 24 Immediately the father of the boy cried out and said, “I believe; help my unbelief!”

25 Now when Jesus saw that a crowd was quickly gathering, he rebuked the unclean spirit, saying to it, “Mute and deaf spirit, I command you, come out of him and never enter him again.” 26 It shrieked, threw him into terrible convulsions, and came out. The boy looked so much like a corpse that many said, “He is dead!” 27 But Jesus gently took his hand and raised him to his feet, and he stood up.

28 Then, after he went into the house, his disciples asked him privately, “Why couldn’t we cast it out?” 29 He told them, “This kind can come out only by prayer.”