Who Is Elias, and Who Is “That Prophet”?

Joseph Smith Translation, John 1:20–24

20 And this is the record of John, when the Jews sent priests and Levites from Jerusalem, to ask him; Who art thou?
21 And he confessed, and denied not that he was Elias; but confessed, saying; I am not the Christ.
22 And they asked him, saying; How then art thou Elias? And he said, I am not that Elias who was to restore all things. And they asked him, saying, Art thou that prophet? And he answered, No.
23 Then said they unto him, Who art thou? that we may give an answer to them that sent us. What sayest thou of thyself?
24 He said, I am the voice of one crying in the wilderness, Make straight the way of the Lord, as saith the prophet Esaias.

Elder Bruce R. McConkie wrote:

“In the time of Jesus and John, the whole Jewish nation was stirred up with anxious expectation, awaiting the momentary appearance of the Messiah and His Elias. With great hosts from Jerusalem and all Judea flocking to John and accepting him as a prophet, and with the banks of the Jordan crowded with his baptized converts, it was natural for the leading Jews—members of the great Sanhedrin, whose obligation it was to test prophetic claims—to send priests and Levites to make detailed investigation. To their pointed questions, John gave bold and authoritative answers:

“Art thou Elias? ‘Yes; I am Messiah’s forerunner, His Elias; I have come in the spirit and power of Elias to prepare the way before Him. I hold the Priesthood of Elias, the Aaronic Priesthood; I baptize with water only. He shall come in the power and authority of the Melchizedek Priesthood and baptize both with water and the Spirit. But, do not be confused, I am not that Elias who was to restore all things, for that Elias is the Messiah Himself; He shall restore all things, even the fulness of the gospel which was had by Adam and Abraham and many of the prophets of old. He shall replace the lesser law of Moses with the high law of Christ.’ . . .

“‘Art thou that prophet like unto Moses whose coming is promised?’ [See John 7:41; Deuteronomy 18:15–22]. ‘No; I am not that prophet, for that prophet is the promised Messiah Himself. He it is who, coming after me, is preferred before me. Instead, I am the prophet whose coming Isaiah foretold [see Isaiah 40:3]; I am the voice of one crying in the wilderness: Prepare ye the way of the Lord, who is the prophet of whom Moses spoke.’

“‘Art thou the Christ?’ ‘No; I am not the Christ; nor am I worthy to fill His place, or even to unloose the very latchet of His shoes. But I bear record of Him; and He now standeth among you, and He is the Son of God.’”

“. . . John’s questioners were familiar with some ancient Messianic prophecy, unknown to us, which foretold the coming of Elias to perform a mighty work of restoration [see JST, John 1:22]. Perhaps it was part of the same prophecy discussed by Peter, James, and John, and our Lord on the Mount of Transfiguration [see Matthew 17:11].”

(Doctrinal New Testament Commentary, 3 vols. [1965–73], 1:129–30.)