Mark 9:17-18

9:17 A member of the crowd said to him, “Teacher, I brought you my son, who is possessed by a spirit that makes him mute. 9:18 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.”

Mark 9:20-22

9:20 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. 9:21 Jesus asked his father, “How long has this been happening to him?” And he said, “From childhood. 9:22 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.”