1 In those days came John the Baptist, preaching in the wilderness of Judea,
2 And saying, Repent ye: for the kingdom of heaven is at hand.
Elder Bruce R. McConkie wrote:
“John’s teaching was ‘the preparatory gospel; which gospel is the gospel of repentance and of baptism, and the remission of sins’ (D&C 84:26–27). Without repentance there is neither forgiveness of sin nor salvation in the celestial realms.
“[John the Baptist taught, ‘Repent ye: for the kingdom of heaven is at hand.’] That is, the kingdom of God on earth, the one true Church, the sole organization through which salvation is administered, the very Church and kingdom is here. ‘John came preaching the Gospel for the remission of sins,’ the Prophet [Joseph Smith] taught. ‘He had his authority from God, and the oracles of God were with him, and the kingdom of God for a season seemed to rest with John alone. . . . But, says one, the kingdom of God could not be set up in the days of John, for John said the kingdom was at hand. But I would ask if it could be any nearer to them than to be in the hands of John. The people need not wait for the days of Pentecost to find the kingdom of God, for John had it with him, and he came forth from the wilderness crying out, “Repent ye, for the kingdom of heaven is nigh at hand” [Matthew 3:2], as much as to say, “Out here I have got the kingdom of God, and you can get it, and I am coming after you; and if you don’t receive it, you will be damned;” and the scriptures represent that all Jerusalem went out unto John’s baptism [see Matthew 3:5–6]. There was a legal administrator, and those that were baptized were subjects for a king; and also the laws and oracles of God were there; therefore the kingdom of God was there; for no man could have better authority to administer than John; and our Savior submitted to that authority Himself, by being baptized by John; therefore the kingdom of God was set up on the earth, even in the days of John’ [Teachings of Presidents of the Church: Joseph Smith (2007), 82, 83].”
(Doctrinal New Testament Commentary, 3 vols. [1965–73], 1:113–14.)