Art thou Elias? - This is the Greek way of writing Elijah. The Jews expected that Elijah would appear before the Messiah came. See the notes at Matthew 11:14. They supposed that it would be the real Elijah returned from heaven. In this sense John denied that he was Elijah; but he did not deny that he was the Elias or Elijah which the prophet intended Matthew 3:3, for he immediately proceeds to state John 1:23 that he was sent, as it was predicted that Elijah would be, to prepare the way of the Lord; so that, while he corrected their false notions about Elijah, he so clearly stated to them his true character that they might understand that he was really the one predicted as Elijah.

That prophet - It is possible that the Jews supposed that not only "Elijah" would reappear before the coming of the Messiah, but also "Jeremiah." See the notes at Matthew 16:14. Some have supposed, however, that this question has reference to the prediction of Moses in Deuteronomy 18:15.

Art thou Elias? - The scribes themselves had taught that Elijah was to come before the Messiah. See Matthew 17:10; and this belief of theirs they supported by a literal construction of Malachi 4:5.

Art thou that prophet? - the prophet spoken of by Moses, Deuteronomy 18:15, Deuteronomy 18:18. This text they had also misunderstood: for the prophet or teacher promised by Moses was no other than the Messiah himself. See Acts 3:22. But the Jews had a tradition that Jeremiah was to return to life, and restore the pot of manna, the ark of the covenant, etc., which he had hidden that the Babylonians might not get them. Besides this, they had a general expectation that all the prophets should come to life in the days of the Messiah.

I am not - I am not the prophet which you expect, nor Elijah: though he was the Elijah that was to come; for in the spirit and power of that eminent prophet he came, proclaiming the necessity of reformation in Israel. See Matthew 11:14; Matthew 17:10-13.

And they asked him, what then? art thou Elias?.... Elijah, the prophet; the Tishbite, as Nonnus in his paraphrase expresses it; who was translated, soul and body, to heaven: the Jews had a notion that that prophet would come in person a little before the coming of the Messiah; See Gill on Matthew 17:10 wherefore these messengers inquire, that since he had so fully satisfied them that he was not the Messiah, that he would as ingenuously answer to this question, if he was Elias, or not:

and he saith, I am not; that is, he was not Elijah the prophet that lived in Ahab's time, and was called the Tishbite; for John's answer is to the intention of their question, and their own meaning in it, and is no contradiction to what Christ says of him, Matthew 11:14 that he was the Elias that was to come; for he was the person meant by him in Malachi 4:5 though not in the sense the Jews understood it; nor is it any contradiction to what the angel said to Zacharias, Luke 1:17 for he does not say that John should come in the body, but in the power and spirit of Elias; See Gill on Matthew 11:14.

Art thou that prophet? Jeremiah, whom some of the Jews (t) have thought to be the prophet Moses spoke of, in Deuteronomy 18:15 and expected that he would appear about the times of the Messiah; see Matthew 16:14 or any one of the ancient prophets risen from the dead, which they also had a notion of, Luke 9:8 or, as it may be rendered, "art thou a prophet?" for prophecy had long ceased with them:

and he answered, no; he was not Jeremiah, nor any one of the old prophets risen from the dead, nor a prophet in the sense they meant: he was not like one of the prophets of the Old Testament; he was a prophet, and more than a prophet, as Christ says, Matthew 11:9 yet not such a prophet as they were; his prophesying lay not so much in predicting future events, as in pointing out Christ, and preaching the doctrine of the remission of sins by him,

(t) Baal Hatturim in Deuteronomy 18.15. Tzeror Hammor, fol. 127. 4. & 143. 4. Siphre in Jarchi in Jer. i. 5.

What then? Art thou Elias?

Better, as Rev., Elijah. Some authorities read, What then art thou? Elijah? Elijah, predicted in Malachi 4:5, as the forerunner of the day of the Lord.

Art thou that prophet?

Rev., "the prophet." According to the Greek order, the prophet art thou. See Deuteronomy 18:15, and compare Acts 3:22; Acts 7:37; John 1:46; John 6:14.

No

Observe how the successive denials become shorter.

And they asked him, What then? Art thou Elias? And he saith, {i} I am not. Art thou {k} that prophet? And he answered, No.

(i) The Jews thought that Elias would come again before the days of the Messiah, and they took as the basis of their opinion Mal 4:5, which is to be understood as referring to John, see Mt 11:14. And yet John denies that he is Elias, answering their question just as they meant it.

(k) They are inquiring about some great prophet, and not about Christ, for John denied before that he is Christ, for they thought that some great prophet would be sent like Moses, using to support this position De 18:15, which is to be understood to refer to all the company of the prophets and ministers, which have been and shall be to the end, and especially of Christ who is the head of all prophets.

1:20,21 He confessed, etc. Some conjectured that John was the expected Christ; others that he was Elijah who was first to come (Mal 4:5); others that he was that prophet, the one predicted by Moses (De 18:15); but he declared that he was none of these.

1:21 Art thou Elijah? - He was not that Elijah (the Tishbite) of whom they spoke. Art thou the prophet - Of whom Moses speaks, Deut 18:15.

that prophet: or, a prophet?

21. Elias-in His own proper person.

that prophet-announced in De 18:15, &c., about whom they seem not to have been agreed whether he were the same with the Messiah or no.

1:19-28 John disowns himself to be the Christ, who was now expected and waited for. He came in the spirit and power of Elias, but he was not the person of Elias. John was not that Prophet whom Moses said the Lord would raise up to them of their brethren, like unto him. He was not such a prophet as they expected, who would rescue them from the Romans. He gave such an account of himself, as might excite and awaken them to hearken to him. He baptized the people with water as a profession of repentance, and as an outward sign of the spiritual blessings to be conferred on them by the Messiah, who was in the midst of them, though they knew him not, and to whom he was unworthy to render the meanest service.