Matthew 17:10-20

And His disciples asked Him, “Why then do the scribes say that Elijah must come first?” And He answered and said, “Elijah is coming and will restore all things; but I say to you that Elijah already came, and they did not recognize him, but did to him whatever they wished. So also the Son of Man is going to suffer at their hands.” Then the disciples understood that He had spoken to them about John the Baptist. When they came to the crowd, a man came up to Jesus, falling on his knees before Him and saying, “Lord, have mercy on my son, for he is a lunatic and is very ill; for he often falls into the fire and often into the water. I brought him to Your disciples, and they could not cure him.” And Jesus answered and said, “You unbelieving and perverted generation, how long shall I be with you? How long shall I put up with you? Bring him here to Me.” And Jesus rebuked him, and the demon came out of him, and the boy was cured at once. Then the disciples came to Jesus privately and said, “Why could we not drive it out?” And He *said to them, “Because of the littleness of your faith; for truly I say to you, if you have faith the size of a mustard seed, you will say to this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible to you.