Mark 9:26-30

And the spirit cried, and rent him sore, and came out of him: and he was as one dead; insomuch that many said, He is dead.

But Jesus took him by the hand, and lifted him up; and he arose.

And when he was come into the house, his disciples asked him privately, Why could not we cast him out?

And he said unto them, This kind can come forth by nothing, but by prayer and fasting.

And they departed thence, and passed through Galilee; and he would not that any man should know it.