Mark 9:14-19

14 And when He came to the disciples, He saw a great multitude around them, and scribes disputing with them.

15 Immediately, when they saw Him, all the people were greatly amazed, and running to Him, greeted Him.

16 And He asked the scribes, "What are you discussing with them?"

17 Then one of the crowd answered and said, "Teacher, I brought You my son, who has a mute spirit.

18 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."

19 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."