Then the disciples understood that he spoke unto them of John the Baptist.
All Commentaries on Matthew 17:13 Go To Matthew 17
Rabanus Maurus
AD 856
From the mention of His own passion which the Lord had often foretold to them, and from that of His forerunner, which they beheld already accomplished, the disciples perceived that John was set forth to them under the name of Elias; whence it follows; “Then understood the disciples that he spake to them of John the Baptist.”