The question of the disciples:
Related Commentaries of Matthew 17:10
Matthew 17:10-13
10 And his disciples asked him, saying, Why then say the scribes that Elias must first come?
11 And Jesus answered and said unto them,Elias truly shall first come, and restore all things.
12 But I say unto you, That Elias 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.
13 Then the disciples understood that he spake unto them of John the Baptist.