A Rod, a Stem, a Branch and Roots
Verses 1 and 10 are very interesting verses. We learn from D&C 113:2 that the stem of Jesse is Christ. The rod is a servant of Christ who is a descendent of both Ephraim and Jesse "on whom there is laid much power" (D&C 113:4). We also learn from section 113 verse 6 that the "root of Jesse" is a descendent of Jesse as well as Joseph (Ephraim) who rightly possess the priesthood and the keys of the kingdom to be an ensign and gatherer of God's people in the last days. The branch is not specifically mentioned in section 113, but the author at gospeldoctrine.com, through some deductive reasoning, postulates that the branch is Christ.
As to the rod and root of Jesse, the same author thinks that both of these represent Joseph Smith. I did a search on the lds.org gospel library and found only three results for "root of Jesse." One result agrees that the rod and root represent Joseph Smith. The other search result returns an article whose author is a Jew who converted to the Church. In that article, he alludes that the root of Jesse is person who is yet to come. He learned this from "various Latter-day prophets." Every time I read this chapter, I've always assumed that the root is not Joseph Smith, but another prophet who is yet to come.
The Knowledge of the Lord
In verses 6-9, we read that the Earth will be "safe" so that the hunter and the hunted will lay down side by side without bloodshed. "They shall not hurt or destroy … for the earth shall be full of the knowledge of the Lord" (v. 9).
Joseph Smith once admonished his fellow saints when some attempted to kill rattlesnakes.
"In pitching my tent we found three massasaguas, or prairie rattlesnakes, which the brethren were about to kill, but I said, 'Let them alone, don't hurt them! How will the serpent ever lose his venom, while the servants of God possess the same disposition, and continue to make war upon it? Men must become harmless, before the brute creation; and when men lose their vicious dispositions and cease to destroy the animal race, the lion and the lamb can dwell together, and the suckling child can play with the serpent in safety.' The brethren took the serpents carefully on sticks and carried them across the creek. I exhorted the brethren not to kill a serpent, bird or an animal of any kind during my journey unless it became necessary in order to preserve ourselves from hunger. (History of the Church, vol. 2, pp. 71-2)"
The Gathering of Israel
As prophesied so many times before, Isaiah yet again prophesies that the lost tribes will return in the Last Days. In D&C 133 we learn more of this "highway for the remnant of his people" (v. 16). D&C 133:26-32 says,
"And they who are in the north countries shall come in remembrance before the Lord; and their prophets shall hear his voice, and shall no longer stay themselves; and they shall smite the rocks, and the ice shall flow down at their presence.
And an highway shall be cast up in the midst of the great deep.
Their enemies shall become a prey unto them,
And in the barren deserts there shall come forth pools of living water; and the parched ground shall no longer be a thirsty land.
And they shall bring forth their rich treasures unto the children of Ephraim, my servants.
And the boundaries of the everlasting hills shall tremble at their presence.
And there shall they fall down and be crowned with glory, even in Zion, by the hands of the servants of the Lord, even the children of Ephraim."
God is my Salvation
In chapter 22, we read that we will rejoice that Christ will reign on the earth.
Verse 2 is my favorite verse in this chapter.
"Behold, God is my salvation; I will trust, and not be afraid; for the Lord JEHOVAH is my strength and my song; he also has become my salvation."
In verse 6, we are reminded that Christ will personally reign on the earth as he will be "in the midst" of Israel.