Matthew 17:10-13

10And his disciples asked him, saying, Why then say the scribes that Elijah must first come?

11And Jesus answered and said unto them, Elijah truly shall first come, and restore all things.

12But I say unto you, That Elijah is come already, and they knew him not, but have done unto him whatsoever they listed. Likewise shall also the Son of man suffer of them.

13Then the disciples understood that he spake unto them of John the Baptist.