Mark 9:14-29 NKJV
And when He came to the disciples, He saw a great multitude around them, and scribes disputing with them. Immediately, when they saw Him, all the people were greatly amazed, and running to Him, greeted Him. And He asked the scribes, “What are you discussing with them?”
Then one of the crowd answered and said, “Teacher, I brought You my son, who has a mute spirit. And wherever it seizes him, it throws him down; he foams at the mouth, gnashes his teeth, and becomes rigid. So I spoke to Your disciples, that they should cast it out, but they could not.”
He answered him and said, “O faithless generation, how long shall I be with you? How long shall I bear with you? Bring him to Me.” Then they brought him to Him. And when he saw Him, immediately the spirit convulsed him, and he fell on the ground and wallowed, foaming at the mouth.
So He asked his father, “How long has this been happening to him?”
And he said, “From childhood. And often he has thrown him both into the fire and into the water to destroy him. But if You can do anything, have compassion on us and help us.”
Jesus said to him, “If you can believe, all things are possible to him who believes.”
Immediately the father of the child cried out and said with tears, “Lord, I believe; help my unbelief!”
When Jesus saw that the people came running together, He rebuked the unclean spirit, saying to it: “Deaf and dumb spirit, I command you, come out of him and enter him no more!” Then the spirit cried out, convulsed him greatly, and came out of him. And he became as one dead, so that many said, “He is dead.” But Jesus took him by the hand and lifted him up, and he arose.
And when He had come into the house, His disciples asked Him privately, “Why could we not cast it out?”
So He said to them, “This kind can come out by nothing but prayer and fasting.”
NKJV: New King James Version