St Mark 9:14-29

And presently all the people seeing Jesus, were astonished and struck with fear; and running to him, they saluted him. And he asked them: What do you question about among you? And one of the multitude, answering, said: Master, I have brought my son to thee, having a dumb spirit. Who, wheresoever he taketh him, dasheth him, and he foameth, and gnasheth with the teeth, and pineth away; and I spoke to thy disciples to cast him out, and they could not. Who answering them, said: O incredulous generation, how long shall I be with you? how long shall I suffer you? bring him unto me. And they brought him. And when he had seen him, immediately the spirit troubled him; and being thrown down upon the ground, he rolled about foaming. And he asked his father: How long time is it since this hath happened unto him? But he said: From his infancy: And oftentimes hath he cast him into the fire and into waters to destroy him. But if thou canst do any thing, help us, having compassion on us. And Jesus saith to him: If thou canst believe, all things are possible to him that believeth. And immediately the father of the boy crying out, with tears said: I do believe, Lord: help my unbelief. And when Jesus saw the multitude running together, he threatened the unclean spirit, saying to him: Deaf and dumb spirit, I command thee, go out of him; and enter not any more into him. And crying out, and greatly tearing him, he went out of him, and he became as dead, so that many said: He is dead. But Jesus taking him by the hand, lifted him up; and he arose. And when he was come into the house, his disciples secretly asked him: Why could not we cast him out? And he said to them: This kind can go out by nothing, but by prayer and fasting. And departing from thence, they passed through Galilee, and he would not that any man should know it.