Matthew 17:16-20

And I brought him to Your disciples, and they could not cure him.”

And Jesus answered and said, “You unbelieving and perverse 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 healed at once.

Then the disciples came to Jesus privately and said, “Why could we not cast it out?”

And He *said to them, “Because of your meager 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 for you.”