(Isa. 11:4; 16:5; D&C 29:11–12; 43:29; 38:21–22)
When that time shall come, the “earth shall be full of the knowledge of the Lord, as the waters cover the sea.” Wickedness shall be destroyed, for with righteousness shall Jehovah “judge the poor, and reprove with equity for the meek of the earth: and he shall smite the earth with the rod of his mouth, and with the breath of his lips shall he slay the wicked.”
In that day there shall be no “divided Christianity.” All who will not repent and receive the gospel shall soon be removed, and they who shall remain shall learn to worship the true and living God in spirit and in truth. The Church of Jesus Christ shall have sway over all the earth, for Christ shall be the King and Deliverer. Peace shall prevail both among men and among beasts. Satan shall be bound and his dominion, which he has held by usurpation and fraud since the beginning of the earth’s temporal existence, shall come to an end. The rightful King shall reign and his saints shall possess the kingdom according to the vision of Daniel (Isa. 65:17–25; D&C 101:23–31; Dan. 7:14, 22, 27).
Jerusalem shall become a righteous city when Israel is gathered and redeemed. Zion also shall be cleansed of all iniquity, and in that day, when Christ shall rule, the word of the Lord to Isaiah shall be fulfilled, “for out of Zion shall go forth the law, and the word of the Lord from Jerusalem” (Isa. 2:3).
(Joseph Fielding Smith, Doctrines of Salvation: Sermons and Writings of Joseph Fielding Smith, ed. Bruce R. McConkie, 3 vols. [Salt Lake City: Bookcraft, 1954–1956], 1:168–69.)
For the righteous and the meek, the judgment shall be a blessing. The coming of Jesus Christ as Judge will improve the justice system of nations and peoples. The courts will not be influenced by the wickedness of corrupt laws and judges that are now part of the fallen earth. As the Prophet Joseph Smith explained, “The world has had a fair trial for six thousand years; the Lord will try the seventh thousand Himself; ‘He whose right it is, will possess the kingdom, … Satan will be bound, and the works of darkness destroyed; … and he that fears the Lord will alone be exalted in that day.’” (Smith, History of the Church, 5:64–65; see also Isa. 28:17.) The hopes and dreams of good people through the ages will be realized as righteousness becomes the standard of judgment and equity is bestowed upon all of the inhabitants of the earth… .
Isaiah wrote that those who have not known the Lord’s name will also be spared at the beginning of the Millennium (see Isa. 66:19). Those who have not known the name of Jesus Christ, or the non-Christian peoples, are referred to as heathen nations. Concerning those who have not known his name, God revealed further clarification to the Prophet Joseph Smith saying that “the heathen nations [shall] be redeemed, and they that knew no law shall have part in the first resurrection; and it shall be tolerable for them” (D&C 45:54). It should be remembered that those who lived in wickedness in mortality or “the spirits of men who are to be judged, and are found under condemnation … live not again until the thousand years are ended” (D&C 88:100–101). But many among the heathen nations will be able to abide a terrestrial law and enjoy the blessings of the Millennium. They are good, honorable people who have been “blinded by the craftiness of men” (D&C 76:75). Further, they will receive a testimony of Jesus in the millennial day or will have received this testimony as spirits prior to coming forth in the resurrection from the dead (D&C 76:72–74).
(Craig J. Ostler, Voices of Old Testament Prophets: The 26th Annual Sidney B. Sperry Symposium [Salt Lake City: Deseret Book Co., 1997], 65–66, 68–69, 83.)
During all these years men dwelling in mortality will have the privilege of associating with those who have received their resurrection. Our Lord and Savior will be a familiar figure among the righteous saints. Instruction will be given by resurrected prophets. How could wickedness remain under such conditions? Those who have passed through the resurrection will not, however, dwell with those in mortality. They will not stay in earthly, or human homes nor sleep in the beds of mortals. Such a thing would be inconsistent. Joseph Smith has said:
Christ and the resurrected Saints will reign over the earth during the thousand years. They will not probably dwell on the earth, but will visit it when they please, or when it is necessary to govern it. There will be wicked men on the earth during the thousand years. The heathen nations who will not come up to worship will be visited with the judgments of God, and must eventually be destroyed from the earth… .
The question naturally will arise, if the wicked are to be destroyed when Christ comes, then how can there be wicked men on the earth during the Millennium, as stated by Joseph Smith and Isaiah? It is quite evident that the “wickedness” during that time will be among those who are heathen, or have not come into the Church, and their wickedness consists of failure to receive the Gospel of Jesus Christ … (D&C 84:50–53).
Men will be free from the temptations of Satan; peace will be in the hearts of all men, and it is decreed that in time all will receive the truth, for the Gospel is to cover the earth as the waters do the sea.
(Joseph Fielding Smith, The Way to Perfection [Salt Lake City: Deseret Book Co., 1968], 312–14.)