Matthew 17:9-19

9 As they were coming down the mountain, Jesus ordered them, "Tell no one about the vision until after the Son of Man has been raised from the dead."
10 And the disciples asked him, "Why, then, do the scribes say that Elijah must come first?"
11 He replied, "Elijah is indeed coming and will restore all things;
12 but I tell you that Elijah has already come, and they did not recognize him, but they did to him whatever they pleased. So also the Son of Man is about to suffer at their hands."
13 Then the disciples understood that he was speaking to them about John the Baptist.
14 When they came to the crowd, a man came to him, knelt before him,
15 and said, "Lord, have mercy on my son, for he is an epileptic and he suffers terribly; he often falls into the fire and often into the water.
16 And I brought him to your disciples, but they could not cure him."
17 Jesus answered, "You faithless and perverse generation, how much longer must I be with you? How much longer must I put up with you? Bring him here to me."
18 And Jesus rebuked the demon, and it came out of him, and the boy was cured instantly.
19 Then the disciples came to Jesus privately and said, "Why could we not cast it out?"

Footnotes 2

New Revised Standard Version Bible, copyright 1989, Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.