Matthew 17:14-19

141When they came to the crowd, a man came up to 2Jesus, falling on his knees before Him and saying, 15“3Lord, have mercy on my son, because he 4has seizures and suffers terribly; for he often falls into the fire and often into the water. 16And I brought him to Your disciples, and they could not cure him.” 17And 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.” 18And Jesus rebuked him, and the demon came out of him, and the boy was healed 5at once.

19Then the disciples came to Jesus privately and said, “Why could we not cast it out?”