During the Millennium, the Celestial and Terrestrial categories of people will live on earth at the same time, while the telestial people suffer in hell. During this time, Christ reigns personally.
For in mine own due time will I come upon the earth in judgment, and my people shall be redeemed and shall reign with me on earth. For the great Millennium, of which I have spoken by the mouth of my servants, shall come.
When this happens, everyone who has lived that is of the celestial or terrestrial category will be restored to life, similar to how Lazarus was raised from the dead. If this is a new concept for you, I recommend you listen to episode 36 of the Iron Rod Podcast. Everyone who has ever lived who didn’t commit telestial-level sins will be raised from the dead and live during the Millennium.
Let’s remind ourselves of a key aspect of the terrestrial category.
And after this another angel shall sound, which is the second trump; and then cometh the redemption of those who are Christ’s at his coming; who have received their part in that prison which is prepared for them, that they might receive the gospel, and be judged according to men in the flesh.
When Christ comes there is a first judgement to select who is currently celestial, terrestrial, and telestial. The terrestrial people who are Christ’s at his coming were judged worthy of being redeemed at Christ’s coming at the beginning of the Millennium. While living in the Millennium, they have the opportunity to receive the gospel while in the flesh so they can later be judged according to men in the flesh at the final judgment on the last day.
How do they receive the gospel? (Receive means not just hearing the gospel, but fully embracing it and receiving all the spiritual benefits described in the scriptures).
And the terrestrial through the ministration of the celestial.
The celestial category of people are there in the Millennium (having come with Christ in the cloud) to teach and minister to the terrestrial category and prepare them to receive the gospel, as D&C 88:99 says. And what happens when someone receives the gospel?
But verily, verily, I say unto you, that as many as receive me, to them will I give power to become the sons of God, even to them that believe on my name. Amen.
Hearken unto the voice of the Lord your God, while I speak unto you, Emma Smith, my daughter; for verily I say unto you, all those who receive my gospel are sons and daughters in my kingdom.
I came unto mine own, and mine own received me not; but unto as many as received me gave I power to do many miracles, and to become the sons of God; and even unto them that believed on my name gave I power to obtain eternal life.
Notice that there are no exclusion clauses here. Anyone who receives the gospel becomes a son or daughter of God, regardless of whether that happens before or during the Millennium. These terrestrial people spent time in prison that they might receive the gospel. The goal is for them to “receive the gospel”. Anyone who receives the gospel becomes a son or daughter of God in his kingdom. which as previous posts have demonstrated, is the celestial kingdom. The terrestrials who receive the gospel become celestial before the great and last day of judgment.
Remember how D&C 76 tells us that God saves all the works of his hands, and he saves all except the sons of perdition? We know you can’t be saved anywhere outside the celestial kingdom. Now we see how the terrestrial category of people are saved…they are taught the fullness of the gospel during the Millennium and in the process of “receiving” it become celestial.
Remember all those scriptures saying the only way to be saved in the kingdom of God is through faith, repentance, baptism by water and fire, etc., and there is no other way or condition to be saved in the kingdom of God? That hasn’t been violated here. These Terrestrials will be in the flesh, restored to their mortal bodies, and exercise faith, repent, and be baptized. They will meet all the conditions necessary for the celestial kingdom.
Remember the Alvin Smith paradox? The paradox is resolved. People like Alvin will be restored to life as terrestrial people in the Millennium (per D&C 76), and celestial people will teach them the gospel until they have achieved their own spiritual birth and become sons and daughters of God, at which point they will have become celestial people (per D&C 137).
Keep in mind, this progression occurs during the Millennium, before the little season when Satan is loosed, and before the great and last day of judgment, which is a binary judgment. Humanity will either be saved in the celestial kingdom, or cast out with the devil and his angels.
Additional scriptural references indicating that terrestrial people (heathens, less valiant, etc.) will progress to a celestial level during the Millennium:
2 Nephi 21:6-9 / Isaiah 11:6-9
6 The wolf also shall dwell with the lamb, and the leopard shall lie down with the kid, and the calf and the young lion and fatling together; and a little child shall lead them.
7 And the cow and the bear shall feed; their young ones shall lie down together; and the lion shall eat straw like the ox.
8 And the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice’s den.
9 They shall not hurt nor destroy in all my holy mountain, for the earth shall be full of the knowledge of the Lord, as the waters cover the sea.
1 The wilderness and the solitary place shall be glad for them; and the desert shall rejoice, and blossom as the rose.
2 It shall blossom abundantly, and rejoice even with joy and singing: the glory of Lebanon shall be given unto it, the excellency of Carmel and Sharon, they shall see the glory of the Lord, and the excellency of our God.
33 Thus saith the Lord God; In the day that I shall have cleansed you from all your iniquities I will also cause you to dwell in the cities, and the wastes shall be builded.
34 And the desolate land shall be tilled, whereas it lay desolate in the sight of all that passed by.
35 And they shall say, This land that was desolate is become like the garden of Eden; and the waste and desolate and ruined cities are become fenced, and are inhabited.
16 The Lord also shall roar out of Zion, and utter his voice from Jerusalem; and the heavens and the earth shall shake: but the Lord will be the hope of his people, and the strength of the children of Israel.
17 So shall ye know that I am the Lord your God dwelling in Zion, my holy mountain: then shall Jerusalem be holy, and there shall no strangers pass through her any more.
10 Sing and rejoice, O daughter of Zion: for, lo, I come, and I will dwell in the midst of thee, saith the Lord.
11 And many nations shall be joined to the Lord in that day, and shall be my people: and I will dwell in the midst of thee, and thou shalt know that the Lord of hosts hath sent me unto thee.
1 Nephi 22
26 And because of the righteousness of his people, Satan has no power; wherefore, he cannot be loosed for the space of many years; for he hath no power over the hearts of the people, for they dwell in righteousness, and the Holy One of Israel reigneth.
27 And now behold, I, Nephi, say unto you that all these things must come according to the flesh.
28 But, behold, all nations, kindreds, tongues, and people shall dwell safely in the Holy One of Israel if it so be that they will repent.
11 For I will reveal myself from heaven with power and great glory, with all the hosts thereof, and dwell in righteousness with men on earth a thousand years, and the wicked shall not stand.