Isaiah 38 - 44

Many of Isaiah's prophecies were regarding the coming of the Messiah and -

"The voice of him that crieth in the wilderness, Prepare ye the way of the LORD, make straight in the desert a highway for our God." (Old Testament Isaiah 40:3)

Luke makes reference of this prophecy as he talks of John the Baptist saying -

"...he came into all the country about Jordan, preaching the baptism of repentance for the remission of sins;
4 As it is written in the book of the words of Esaias the prophet, saying, The voice of one crying in the wilderness, Prepare ye the way of the Lord, make his paths straight." (New Testament Luke 3:3 - 4)

There is no question Isaiah's prophecy is in regards to John the Baptist. What is interesting is what follows both in Isaiah and in Luke writings -

"...Every valley shall be exalted, and every mountain and hill shall be made low: and the crooked shall be made straight, and the rough places plain..." (Old Testament Isaiah 40:4)

I don't remember this necessarily happening in the old world. The words of Isaiah sometimes seem to be more in reference to the second coming than that in the meridian of time. As Isaiah begins this prophecy, he writes -

"COMFORT ye, comfort ye my people, saith your God.
2 Speak ye comfortably to Jerusalem, and cry unto her, that her warfare is accomplished, that her iniquity is pardoned: for she hath received of the LORD's hand double for all her sins." (Old Testament Isaiah 40:1 - 2)

We know for sure that at that time, Judah's warfare was not accomplished or her inquity pardoned. The Savior acknowledges this was not the case as he tells the Pharissees -

"O Jerusalem, Jerusalem, which killest the prophets, and stonest them that are sent unto thee; how often would I have gathered thy children together, as a hen doth gather her brood under her wings, and ye would not!
35 Behold, your house is left unto you desolate..." (New Testament Luke 13:34 - 35)

He follows with -

"...verily I say unto you, Ye shall not see me, until the time come when ye shall say, Blessed is he that cometh in the name of the Lord." (New Testament Luke 13:35)

This verse in itself suggest that he will not come until there is one that cometh in the name of the Lord or also again as a -

"...voice of him that crieth in the wilderness..." (Old Testament Isaiah 40:3)

This again could have reference to John the Baptist in these days which the Lord said -

"...I have sent unto you, my servants, Joseph Smith, Jun., and Oliver Cowdery, to ordain you unto the first priesthood which you have received, that you might be called and ordained even as Aaron..." (Doctrine and Covenants Section 27:8)

President Joseph Fielding Smith said -

“The Lord declared, through one of his prophets, that before his second coming a messenger should be sent to prepare the way and make it straight. You may apply this to John if you will, and it is true. John, the messenger who came to prepare the way before the Lord in the former dispensation, also came in this dispensation as a messenger to Joseph Smith; so it applies, if you wish to apply it so, to John who came as a messenger to prepare the way before the Lord.

But I go farther and maintain that Joseph Smith was the messenger whom the Lord sent to prepare the way before him. He came, and under direction of holy messengers laid the foundation for the kingdom of God and of this marvelous work and a wonder that the world might be prepared for the coming of the Lord.” (Doctrines of Salvation, 1:193–95.)

For -

"Who hath directed the Spirit of the LORD, or being his counsellor hath taught him?
14 With whom took he counsel, and who instructed him, and taught him in the path of judgment, and taught him knowledge, and shewed to him the way of understanding?" (Old Testament Isaiah 40:13 - 14)

These verses suggest more that would come is his name such as latter-day prophets. And the establishment of His Church or His Mountain saying -

"O Zion, that bringest good tidings, get thee up into the high mountain; O Jerusalem, that bringest good tidings, lift up thy voice with strength; lift it up, be not afraid; say unto the cities of Judah, Behold your God!
10 Behold, the Lord GOD will come with strong hand, and his arm shall rule for him: behold, his reward is with him, and his work before him.
11 He shall feed his flock like a shepherd: he shall gather the lambs with his arm, and carry them in his bosom, and shall gently lead those that are with young." (Old Testament Isaiah 40:9 - 11)