In this verse, Moroni speaks of the ancient city of Jerusalem which has since been rebuilt to be the gathering place for the house of Israel. The redemption of Jerusalem is the time when all the promises given to the house of Israel will be fulfilled. This is the redemption of the Millenial Jerusalem which Isaiah spoke of frequently, Break forth into joy, sing together, ye waste places of Jerusalem: for the Lord hath comforted his people, he hath redeemed Jerusalem (Isa 52:9). While Moroni is referring to Jerusalem during the Millenium, he undoubtedly saw the transformation it would undergo after the Millenium—as he admits, I was about to write more, but I am forbidden (v. 13).
Joseph Smith explained the difference between the New Jerusalem and the Old Jerusalem:
“Now many will feel disposed to say, that this New Jerusalem spoken of, is the Jerusalem that was built by the Jews on the eastern continent. But you will see, from Revelation 21:2, there was a New Jerusalem coming down from God out of heaven, adorned as a bride for her husband; that after this, the Revelator was caught away in the Spirit, to a great and high mountain, and saw the great and holy city descending out of heaven from God. Now there are two cities spoken of here.” (Teachings of the Prophet Joseph Smith, p. 86, italics added)
Some elaboration on the Prophets remarks is in order. The Prophet quotes Revelation chapter 21 to show the differences between the two cities, saying “there are two cities spoken of here.” This subject is of particular interest because both the New Jerusalem and the Old Jerusalem are to be met by a city coming out of heaven. However, the circumstances and timing are different.
"And I John saw the holy city, new Jerusalem, coming down from God out of heaven, prepared as a bride adorned for her husband.
And I heard a great voice out of heaven saying, Behold the tabernacle of God is with men, and he will dwell with them’ (Rev 21:2-3).
The prophet taught that this description of the New Jerusalem should not be confused with the other holy city which John saw coming out of heaven:
’And he carried me away in the spirit to a great and high mountain, and shewed me that great city, the holy Jerusalem, descending out of heaven from God.’ (Rev 21:10)
This passage speaks of a heavenly Jerusalem which will come out of heaven just as the Enoch’s Zion will come out of heaven to the New Jerusalem. The key to understanding this is that this heavenly Jerusalem spoken of in Rev 21:10 does not come until after the Millenium. The two cities are compared in the following table:
Heavenly New Jerusalem
Heavenly Old Jerusalem
Description: a city which is to come from heaven and be joined with the New Jerusalem
Description: a city which is to come from heaven and be joined with the Old Jerusalem
Timing: beginning of Millenium
Timing: after the Millenium
Temple: large temple in the city will be the site of extensive temple work during the Millenium
Temple: no temple is necessary because the work has already been done, hence John saw no temple therein (Rev 21:22)
Inhabitants: the people of Enoch (Moses 7:62-64)
Inhabitants: an innumerable company of angels…the general assembly and the church of the firstborn (Heb 12:22-23)
Glory: established after the first heaven and the first earth were passed away (Rev 21:1) when the earth becomes a terrestrialized sphere
Glory: comes after a second heaven and a second earth have passed away, when the earth becomes a celestialized sphere
Leadership: The Son of God will dwell with men for a thousand years
Leadership: Both the Father and the Son will reign, for the Lord God Almighty and the Lamb are the temple of it (Rev 21:22)
Other scriptures which speak of this heavenly city of Jerusalem are Rev 21:9-27; 22:1-5, Heb 11:9-16; 12:22-23.
Joseph Fielding Smith
“After the close of the millennial reign we are informed that Satan, who was bound during the millennium, shall be loosed and go forth to deceive the nations. Then will come the end. The earth will die and be purified and receive its resurrection. During this cleansing period the City Zion, or New Jerusalem, will be taken from the earth; and when the earth is prepared for the celestial glory, the city will come down according to the prediction in the Book of Revelation.” (Answers to Gospel Questions 2:105 as taken from Jerusalem: The Eternal City, by Galbraith, Ogden, and Skinner p. 550)
LeGrand Richards
“There are those who do not understand why there should be no temple in this ’holy Jerusalem.’ The fact is that when the thousand years are ended, the temple work will all have been done, and therefore we will have no more use for a temple, just as we learn from verse 23 (Rev 21) that we will have no further need of the moon by night or the sun by day, ’for the glory of God did lighten it, and the Lamb is the light thereof.’” (A Marvelous Work and a Wonder, p. 327)