Mark 9:17-19

And one of the multitude answered and said, Master, I have brought unto thee my son, which hath a dumb spirit; and wheresoever he taketh him, he teareth him: and he foameth, and gnasheth with his teeth, and pineth away: and I spake to thy disciples that they should cast him out; and they could not. He answereth him, and saith, O faithless generation, how long shall I be with you? how long shall I suffer you? bring him unto me.