Matthew 17:18-21

Jesus commanded the demon inside the boy. Then the demon came out, and the boy was healed from that time on. The followers came to Jesus when he was alone and asked, “Why couldn’t we force the demon out?” Jesus answered, “Because your faith is too small. I tell you the truth, if your faith is as big as a mustard seed, you can say to this mountain, ‘Move from here to there,’ and it will move. All things will be possible for you. [That kind of spirit comes out only if you use prayer and fasting.]”