Mark 9:14-18

Now when they came down the mountain to the other nine disciples, they noticed a large crowd of people gathered around them, with the religious scholars arguing with them. The crowd was astonished to see Jesus himself walking toward them, so they immediately ran to welcome him. “What are you arguing about with the religious scholars?” he asked them. A man spoke up out of the crowd. “Teacher,” he said, “I have a son possessed by a demon that makes him mute. I brought him here to you, Jesus. Whenever the demon takes control of him, it knocks him down, and he foams at the mouth and gnashes his teeth, and his body becomes stiff as a board. I brought him to your disciples, hoping they could deliver him, but they were not able to do it.”