Matthew 17:19-21

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.]”