Adam Clarke's Commentary on the Bible - Matthew 17:13
Then the disciples understood - When he spoke of the sufferings of this prophetic Elijah, and also of his own, which had been the subject of the conversation on the mount, during the transfiguration, they clearly apprehended that he spoke of John the Baptist. read more
Adam Clarke's Commentary on the Bible - Matthew 17:12
Knew him not - Or, ουκ επιγνωσαν αυτον , They have not acknowledged him. That is, the Jewish rulers have not acknowledged him, did not receive him as the forerunner of the Messiah. But it appears that all the rest acknowledged him as such; and some, from the power and demonstration of his preaching, were inclined to think he was more, even the Messiah himself: see Luke 3:15 . read more