Mark 9:13-19
English Standard Version
14And when they came to the disciples, they saw a great crowd around them, and scribes arguing with them.
15And immediately all the crowd, when they saw him, were greatly amazed and ran up to him and greeted him.
16And he asked them, "What are you arguing about with them?"
17And someone from the crowd answered him, "Teacher, I brought my son to you, for he has a spirit that makes him mute.
18And whenever it seizes him, it throws him down, and he foams and grinds his teeth and becomes rigid. So I asked your disciples to cast it out, and they were not able."
19And he answered them, "O faithless generation, how long am I to be with you? How long am I to bear with you? Bring him to me."