A large crowd met them when they came down from the mountain the next day. Scribes were arguing with the rest of the disciples. Jesus asked them “What are you arguing with them about?”
A man in the crowd answered, saying “Lord, have compassion on my only son. He has a spirit that makes him shriek instead of being able to speak normally. Often the spirit seizes him and makes him have convulsions. He foams at the mouth, grinds his teeth, and becomes rigid when this happens. The spirit often throws him to the ground or into fire or water. I asked your disciples to drive the demon out of my son but they couldn’t.”
Jesus said “You unbelieving and corrupt generation! How long will I be here with you to help you out? How long must I put up with your lack of faith? Bring your son to me.”
They brought the boy, and when the spirit saw Jesus it immediately made the boy have convulsions. He fell on the ground, rolling around, and was foaming at the mouth.
Jesus asked the father “How long has this been happening?” “From his childhood,” said the boy’s father. “It has often tried to destroy him. If you are able to, have compassion on us and help us.”
“’If you are able’? Everything is possible if you believe.” The boy’s father immediately cried out “I believe! Help my unbelief!”
Then Jesus noticed a large crowd was quickly gathering around them. Jesus rebuked the unclean spirit, saying “You deaf and mute spirit, I command you to come out of him and never enter him again.” It came out of the boy, making him violently convulse and shriek. Many people in the crowd thought he was dead. But Jesus took him by the hand, helped him stand up, and gave him back to his father. The boy was healed from that moment on. The crowd was amazed at the greatness of God.
Later the disciples asked him privately, “Why couldn’t we drive it out?” He told them “This kind of spirit can only come out by prayer and fasting.”
MT 17:14-21, MK 9:14-29, LK 9:37-42