“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.”
King James Version (KJV)
17:12 Elijah is come already - And yet when the Jews asked John, Art thou Elijah? He said, I am not, #John 1:21|. His meaning was, I am not Elijah the Tishbite, come again into the world. But he was the person of whom Malachi prophesied under that name.
Mt 17:12 Elias is come already. John the Baptist, who came in the spirit and power of Elijah (Mr 1:2-8 Lu 1:17). Have done unto him whatsoever they listed. "List" and "lust" were originally one word, meaninf to "desire" or "wish". The account of his martyrdom is given in Mt 14:6-12 and Mr 6:21-29. The Son of man suffer by them. Henceforth he keeps the lesson of his suffering constantly before their minds. After all, his disciples were not prepared for it when the hour came.