How can there be mortals in the millennial kingdom (pre-mill post trib)?

Question

In light of passages like 1 Corinthians 15:52-53 which states that only after the “dead in Christ are raised” then those who are alive are “changed… putting on immortality” and the teaching on the judgement of the sheep and goats in Matthew 25:31-46 which takes place at the inauguration of the Millennium, when the non-believers will “depart into eternal punishment” and believers into eternal life…

WHO will remain in perishable bodies (capable of reproducing) to repopulate the earth, thus producing the generations up to the final rebellion?

Whether you hold to a pre- mid- or post-tribulation rapture, there still stands the passage in 1 Corinthians 15 I cited above; you can’t allow for a parousia without first experiencing the resurrection or the putting on of immortality.

This has been troubling me for a while, but I’ve concocted a few ways to marry these passages in light of post-trib eschatology… firstly; that “all” of Israel are converted just after the “harpazo” to fulfill Zechariah 12:10 thus they won’t put on immortality.

OR

(THEORY) The multitude of victims of child sacrifice/abortion/infanticide are resurrected into an edenic state and those of us who have put on immortality are tasked with ruling them alongside Jesus with the rod of iron. Because they weren’t in-dwelt with the Spirit but (generally agreed upon) saved by grace nonetheless. Bonus: What do YOU suspect will happen when these fetuses/babies/children are bodily resurrected?

Finally, what if there are pregnant believers that enter the millennial kingdom? And what of the children who haven’t reached the “age of accountability?”

Thanks in advance!

Answer 1

The simplest answer is that the mortals of the millennium are the unbelievers who survive Christ's second coming, and their descendants. This position is advocated by Wayne Grudem in Systematic Theology chapter 55.

However, it is important to recognize that this is a question which the Scripture does not answer in clear terms. Revelation 20 simply does not mention where the unbelievers come from at the end of the millennium, except that they are "at the ends of the earth" (v.8), but that clearly has no implications about who they are or how they relate to the people alive on earth at the parousia. Evidence for them being survivors among the unbelievers derives from two places:

First, as you rightly point out, both 1st Corinthians 15 and 1st Thessalonians 4 indicate that the believers both alive and dead will enter into the millennium with their resurrection, glorified bodies. Luke 20:35-36 indicates that the resurrected believers will neither die nor marry (which presumably implies they will not have children as well).

Secondly, note that Zechariah 14:16 indicates that there will be survivors of Armageddon, so the "all flesh" of Revelation 19:18 should be taken as the whole army assembled against the returning Jesus, and not as all people without exception. Therefore, not everyone who enters into the millennium will be believers going in with resurrection bodies.

Putting these two facts together, it seems natural to suppose that the rebels at the end of the millennium are descendants of the unbelievers who were left alive after the parousia. (Whether any of those unbelievers or their descendants will be saved is a difficult question to answer. Grudem believes that many will be saved (Systematic Theology p.1112), but I have heard other premillennialists disagree.)

On the final judgment

Note that the sheep-and-goats judgment of Matt. 25 is most naturally understood as referring to the same thing as the final judgment occuring at the end of the millennium (Rev.20:11-15). This can in part be seen from the destinies of the two groups in v.46: "[the wicked] will go into eternal punishment, but the righteous into eternal life." The righteous going into eternal life would indicate that this group has glorified bodies at this time. The millennium, therefore, is condensed into verse 31.

I confess to not having read many dispensationalist sources that would advocate for distinguishing the two judgments. However, none of the discrepancies between Matt. 25 and Rev.20:11-15 alleged by Matt Waymeier in Amillennialism and the Age to Come ch.8 are contradictions if we take them as things mentioned in one passage but not the other, except for his assertion that the judgment of Matt.25 takes place on the earth while that of Rev.20 takes place after the earth has passed away. However, nothing like this is stated anywhere in Matt.25 nor in Matt.24:31 which he also cites for this opinion, neither does Rev.20 clearly indicate that the earth has already "passed away" (Rev.21:1) by the time the judgment occurs.

Addressing other opinions

Children of Millennial Believers

Irenaeus suggested that the believers who were still alive on the earth at the parousia will have children during the millennium (Against Heresies Book V chapter 35), however those believers will still be freed from death:

In the times of the kingdom, the righteous man who is upon the earth shall then forget to die. (Against Heresies V.36.2)

The difficulty with this point of view is that 1st Thess. 4 and 1st Cor. 15 indicate that the believers on the earth at the time of Christ's coming will be glorified at that time, so Irenaeus's view would require us to believe that this glorification does not indicate a transformation into the state that Jesus describes in Luke 20:35-36 of the marriage-less "equal to the angels", and thus the "resurrection" Jesus mentions here is not the same as the one Paul mentions in his epistles. (This difficulty also arises if we understand the resurrected believers as having children during the millennium, an argument I have heard from a modern-day premillennialist pastor.)

The Church vs. Israel

Dispensationalists believe that the Church and Israel are two different groups, and those Rapture verses in 1st Thess. 4 and 1st Corinthians 15 are referring only to the Church. The obvious issue with this is that neither of those passages indicate any distinction being made between the faithful among Gentiles and Jews.

In fact, the Scriptural support for making this distinction at all is pretty tenuous. Dispensationalists will usually cite Romans 11:25-32 to defend this position. However, this follows on the heels of the olive-tree metaphor of vv.11-24, which portrays Jewish and Gentile believers being part of a single olive tree. And the whole discussion of chapters 9-11 is prefaced with the declaration:

For not all who are descended from Israel belong to Israel, and not all are children of Abraham because they are his offspring. ~ Romans 9:6-7

Elsewhere Paul clearly indicates that Christians are the children of Abraham by faith (Gal. 3-4) and that, though formerly excluded from citizenship of Israel, we are now included with no wall of separation (Eph. 2-3). This inclusion of Gentiles into Israel was prophesied in the OT (Psalm 87, Zech.2:11, Ezekiel 47:22-23, Isa. 14:1, 19:22-25, 56:3-8, Zeph. 3:9-10). In light of this the NT cites OT prophecies referring to Israel as applicable to the church in numerous places (1st Peter 2:25, Romans 9:25-26, 2nd Corinthains 6:2,6:16-18, Hebrews 8:8-12), and often uses Israel-ish language to talk about the Church (Luke 3:8, 1 Pet. 1:1, 2:9, 2:11-12, 3:6, 4:3, Gal. 6:16, Rev. 3:9, Jam. 1:1, Col. 2:11, 1 Cor. 10:1). God has clearly indicated that inclusion in his covenant community is not a matter of genetics, nor was it in the OT times either (Gen. 17:12, Ruth 1:16, Josh. 8:33,35, Deut. 31:12, Exodus 12:42-49).

In short, given what the Scripture says, it is no wonder that the early church saw itself as the inheritor through Christ of the OT Israelite identity (Epistle of Barnabas 13-14, First Epistle of Clement 29-32). This perspective was, with slight variations, the only view on Israel-Church relations within Christian theology until the 19th century when Dispensationalism first appeared. (Note: This is not to say that the historical church disbelieved in a future ingathering of Jews. See for example Augustine, City of God book XX.29. Rather, they say this ingathering as an ingathering into the Church and not as a distinct people of God.)

Amillennialism

Another way to reconcile this difficulty is to rethink the meaning of the millennium itself. Amillennialists understand the millennium of Rev.20 as referring to the church age (City of God XX.7) which began with Christ's first coming, when he bound Satan in order to plunder his possessions (Mark 3:23-27), but he will be released near the end to make war on the Church (c.f. 2. Thess. 2:1-12), a time period corresponding to the Tribulation. The "first resurrection" refers to the passing from death to life (Eph. 2:1-7) which believers undergo at conversion (note also the parallel of "seated us with him in heavenly places" (Eph. 2:4) with "thrones" (Rev. 20:4)).

This view is often criticized for being too allegorical, especially in how amillennialists usually handle OT prophecies such as Zech. 14 and Isa. 65:17-25.

(Disclaimer: Amillennialism is my own view, and the difficulty of answering your question within a premillennialist perspective is one of the reasons why. If I have unfairly represented any premillennialist view please let me know.)

Fetuses and babies

This is another area where Scripture does not speak plainly. I have heard a premillennialist pastor suggest the same as your theory, that the millennial kingdom will be populated by the souls of aborted fetuses and those who died as infants.

The Bible does have a few things to say that are relevant to this issue, so we do have some foundation from which to draw inferences. We know that sin begins in the womb (Psalm 51:5) and therefore salvation of the unborn must be based on God's grace, not on their innocence. And we also know that God does apply grace to some unborn babies (Romans 9:11). The story of John the Baptist leaping for joy in the womb (Luke 1:41) implies that it is possible for someone to exhibit faith even before they are born.

I would say, on the basis of all these facts, that salvation works the same way for infants and small children as it does for adults: Those who are saved are saved by God's grace through the gift of faith (Eph. 2:8). The work of the Holy Spirit in salvation is not limited by the cognitive capacity of a person.

Regarding your question about pregnant women in the resurrection, I don't know of any passage that is relevant to this issue. While he doesn't comment directly on the issue, I think Augustine's discussion in City of God XXII.12-21 is relevant. We must remember God's omnipotence - God can surely, without difficulty, take the fetus out of the pregnant woman and give it a glorified, immortal body. It's a little strange to imagine, especially what might happen if the woman were saved and the infant not or vice-versa, but I see no great difficulty posed by this.

Of course, there are other possibilities. I don't know what the answer is, but I'm excited to find out!

Answer 2

I hold to an amillennial position in which the account in Revelation 20 refers to the martyred saints in heaven reigning with glorified bodies for a symbolic period of time. This seem to fit in with the harrowing of hades described in Matthew 27:52-53.

But I’m not so convinced that I would jump in the lake of fire if an announcement was made, at the end of the age, that there would be a millennium. The most troubling aspect for those holding to amillennialism is the number of church fathers, who were relatively close to the apostles, who held an historic pre-millennial position. If amillennialism was taught by the Apostle John, why did those (e.g. Irenaeus, etc.) who studied under his immediate followers (e.g. Polycarp) not pass on the proper interpretation?

One of the least troubling ways for a pre-millennial position to work out, with mortals coexisting with immortals, is to view the resurrected saints as reigning from a distance. This might involve only brief appearances taking place from time to time. In that sense, they would be taking on the role of angels as described by Jesus in Luke 20:35-36.

As an analogy, consider the resurrected saints in Matthew 27:52-53. They likely engaged in only a limited amount of activity when they visited Jerusalem on their way to heaven. Their presence might have been very similar to flashing angelic encounters or apparitions of saints, that have sometimes been claimed to have occurred in church history. As a Protestant example, there is J.B Phillips who was a well known Bible translator of the highly regarded Phillips Translation. Phillips describes an experience of how (emphasis added):

… the late C.S. Lewis, whom I did not know very well, and had only seen in the flesh once, but with whom I had corresponded a fair amount, gave me an unusual experience. A few days after his death, while I was watching television, he ‘appeared’ sitting in a chair within a few feet of me, and spoke a few words which were particularly relevant to the difficult circumstances through which I was passing. He was ruddier in complexion than ever, grinning all over his face and, as the old-fashioned saying has it, positively glowing with health. The interesting thing to me was that I had not been thinking about him at all. I was neither alarmed nor surprised…. He was just there — ‘large as life and twice as natural'! A week later, this time when I was in bed reading before going to sleep, he appeared again, even more rosily radiant than before, and repeated the same message, which was very important to me at the time. I was a little puzzled by this, and I mentioned it to a certain saintly Bishop who was then living in retirement here in Dorset. His reply was, ‘My dear J…., this sort of thing is happening all the time’.” (89-90)

Answer 3

1 Corinthians 15 (NLT):

⁴⁸ Earthly people are like the earthly man, and heavenly people are like the heavenly man. ⁴⁹ Just as we are now like the earthly man, we will someday be like the heavenly man. ⁵⁰ What I am saying, dear brothers and sisters, is that our physical bodies cannot inherit the Kingdom of God. These dying bodies cannot inherit what will last forever. ⁵¹ But let me reveal to you a wonderful secret. We will not all die, but we will all be transformed! ⁵² It will happen in a moment, in the blink of an eye, when the last trumpet is blown. For when the trumpet sounds, those who have died will be raised to live forever. And we who are living will also be transformed. ⁵³ For our dying bodies must be transformed into bodies that will never die; our mortal bodies must be transformed into immortal bodies.

By "we", Paul is referring only to Christians, not to all of mankind.

He describes the same event (notice the explicit "believers") in 1 Thessalonians 14 (NLT):

¹⁴ For since we believe that Jesus died and was raised to life again, we also believe that when Jesus returns, God will bring back with him the believers who have died. ¹⁵ We tell you this directly from the Lord: We who are still living when the Lord returns will not meet him ahead of those who have died. ¹⁶ For the Lord himself will come down from heaven with a commanding shout, with the voice of the archangel, and with the trumpet call of God. First, the Christians who have died will rise from their graves. ¹⁷ Then, together with them, we who are still alive and remain on the earth will be caught up in the clouds to meet the Lord in the air. Then we will be with the Lord forever.

And John describes it in Revelation 20 (NLT):

⁴ Then I saw thrones, and the people sitting on them had been given the authority to judge. And I saw the souls of those who had been beheaded for their testimony about Jesus and for proclaiming the word of God. They had not worshiped the beast or his statue, nor accepted his mark on their forehead or their hands. They all came to life again, and they reigned with Christ for a thousand years. ⁴ This is the first resurrection. (The rest of the dead did not come back to life until the thousand years had ended.) ⁴ Blessed and holy are those who share in the first resurrection. For them the second death holds no power, but they will be priests of God and of Christ and will reign with him a thousand years.

When Christ returns, the elect (both dead and alive) will be instantaneously transformed into immortal spirit beings in the first general resurrection. They will rule and teach with Christ in the Kingdom of God for the next thousand years.

In Matthew 24 (NLT), Jesus describes the end times:

²¹ For there will be greater anguish than at any time since the world began. And it will never be so great again. ²² In fact, unless that time of calamity is shortened, not a single person will survive. But it will be shortened for the sake of God’s chosen ones.

The survivors of the great Tribulation will remain on Earth, living and working with Christ and the resurrected saints in the Kingdom of God.

It will be another thousand years before the second general resurrection, when the vast majority of mankind that has ever lived will be resurrected in mortal physical bodies. In the Kingdom, they will be taught God's way and be offered their opportunity for salvation and immortality. (This includes the billions of people that never even heard the name Jesus, the only name by which one can be saved.)

At the end, a relatively small number of people will still refuse God's spirit. They will be mercifully destroyed in the lake of fire.

Answer 4

It all fits together perfectly when "rightly divided" (2 Timothy 2:15 KJV). Paul's heavenly church, the body of Christ, will be "caught up in the clouds" with Christ when the last believer believes in Paul's gospel of God's grace, which is Christ crucified for the forgiveness of all of our sins (1 Corinthians 15:1-4). This will occur prior to Christ physically returning to earth to establish His millennial reign with Peter's earthly church of believing Jews in Christ (being their Messiah) that began at Pentecost, and the gospel of their earthly kingdom of heaven finally being "at hand", as was promised to their fathers (Abraham, Issac, and Jacob):

Paul to his followers regarding Israel:

Romans 11:11

I say then, Have they stumbled that they should fall? God forbid: but rather through their fall salvation is come unto the Gentiles, for to provoke them to jealousy.

Romans 11:25-28

For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in. 26 And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob: 27 For this is my covenant unto them, when I shall take away their sins. 28 As concerning the gospel, they are enemies for your sakes: but as touching the election, they are beloved for the father's sakes.

Paul regarding the 'catching away' of the church, the body of Christ:

1 Thessalonians 4:13-18

But I would not have you to be ignorant, brethren, concerning them which are asleep, that ye sorrow not, even as others which have no hope. 14 For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him. 15 For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep. 16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: 17 Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord. 18 Wherefore comfort one another with these words.

Israel, however, must "endure unto the end" of their final prophetic seven-year tribulation, at which point Christ will return for their "times of refreshing", when their post-cross sins will be "blotted out". This period of tribulation will begin at some point soon after the 'catching away' of the church, the current called out body of believers (Ephesians 3:2).

Christ to Israel regarding the tribulation:

Matthew 24:21-31

For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be. 22 And except those days should be shortened, there should no flesh be saved: but for the elect's sake those days shall be shortened. 23 Then if any man shall say unto you, Lo, here is Christ, or there; believe it not. 24 For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect. 25 Behold, I have told you before. 26 Wherefore if they shall say unto you, Behold, he is in the desert; go not forth: behold, he is in the secret chambers; believe it not. 27 For as the lightning cometh out of the east, and shineth even unto the west; so shall also the coming of the Son of man be. 28 For wheresoever the carcase is, there will the eagles be gathered together. 29 Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken: 30 And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory. 31 And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other.

The disciples to Christ regarding the timing of their promised earthly kingdom of heaven:

Acts 1:6-11

When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel? 7 And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power. 8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth. 9 And when he had spoken these things, while they beheld, he was taken up; and a cloud received him out of their sight. 10 And while they looked stedfastly toward heaven as he went up, behold, two men stood by them in white apparel; 11 Which also said, Ye men of Galilee, why stand ye gazing up into heaven? this same Jesus, which is taken up from you into heaven, shall so come in like manner as ye have seen him go into heaven.

Peter to "Ye men of Israel" trying to convince them of Christ being their Messiah:

Acts 3:12-21

And when Peter saw it, he answered unto the people, Ye men of Israel, why marvel ye at this? or why look ye so earnestly on us, as though by our own power or holiness we had made this man to walk? 13 The God of Abraham, and of Isaac, and of Jacob, the God of our fathers, hath glorified his Son Jesus; whom ye delivered up, and denied him in the presence of Pilate, when he was determined to let him go. 14 But ye denied the Holy One and the Just, and desired a murderer to be granted unto you; 15 And killed the Prince of life, whom God hath raised from the dead; whereof we are witnesses. 16 And his name through faith in his name hath made this man strong, whom ye see and know: yea, the faith which is by him hath given him this perfect soundness in the presence of you all. 17 And now, brethren, I wot that through ignorance ye did it, as did also your rulers. 18 But those things, which God before had shewed by the mouth of all his prophets, that Christ should suffer, he hath so fulfilled. 19 Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord. 20 And he shall send Jesus Christ, which before was preached unto you: 21 Whom the heaven must receive until the times of restitution of all things, which God hath spoken by the mouth of all his holy prophets since the world began.

Paul's church, the body of Christ, is not appointed to this wrath, as we are under God's current age of grace (Ephesians 3:2) and are to be "comforted" in knowing this:

1 Thessalonians 5:1-11

But of the times and the seasons, brethren, ye have no need that I write unto you. 2 For yourselves know perfectly that the day of the Lord so cometh as a thief in the night. 3 For when they shall say, Peace and safety; then sudden destruction cometh upon them, as travail upon a woman with child; and they shall not escape. 4 But ye, brethren, are not in darkness, that that day should overtake you as a thief. 5 Ye are all the children of light, and the children of the day: we are not of the night, nor of darkness. 6 Therefore let us not sleep, as do others; but let us watch and be sober. 7 For they that sleep sleep in the night; and they that be drunken are drunken in the night. 8 But let us, who are of the day, be sober, putting on the breastplate of faith and love; and for an helmet, the hope of salvation. 9 For God hath not appointed us to wrath, but to obtain salvation by our Lord Jesus Christ, 10 Who died for us, that, whether we wake or sleep, we should live together with him. 11 Wherefore comfort yourselves together, and edify one another, even as also ye do.

While Israel will be judging the twelve tribes of Israel on earth during the millennial reign of Christ, the heavenly church, the body of Christ (us today), will be judging angels in heaven:

Christ speaking to the twelve and believing Israel:

Matthew 19:28

And Jesus said unto them, Verily I say unto you, That ye which have followed me, in the regeneration when the Son of man shall sit in the throne of his glory, ye also shall sit upon twelve thrones, judging the twelve tribes of Israel.

Paul speaking to believers in the gospel of God's grace:

1 Corinthians 6:3

Know ye not that we shall judge angels? how much more things that pertain to this life?

Paul was the first member and leader of our church, and the pattern to follow from the appointment that Christ ascended gave him going forward:

1 Timothy 1:16

Howbeit for this cause I obtained mercy, that in me first Jesus Christ might shew forth all longsuffering, for a pattern to them which should hereafter believe on him to life everlasting.

Romans 15:8

Now I say that Jesus Christ was a minister of the circumcision for the truth of God, to confirm the promises made unto the fathers:

Paul makes it clear that we are to follow Christ's heavenly ministry to us, not Christ's earthly ministry to Israel:

2 Corinthians 5:16

Wherefore henceforth know we no man after the flesh: yea, though we have known Christ after the flesh, yet now henceforth know we him no more.

1 Corinthians 4:14-16

I write not these things to shame you, but as my beloved sons I warn you. 15 For though ye have ten thousand instructers in Christ, yet have ye not many fathers: for in Christ Jesus I have begotten you through the gospel. 16 Wherefore I beseech you, be ye followers of me.

1 Corinthians 11:1

Be ye followers of me, even as I also am of Christ.

Philippians 3:17

Brethren, be followers together of me, and mark them which walk so as ye have us for an ensample.

Colossians 1:25

Whereof I am made a minister, according to the dispensation of God which is given to me for you, to fulfil the word of God;

Ephesians 3:1-9

For this cause I Paul, the prisoner of Jesus Christ for you Gentiles, 2 If ye have heard of the dispensation of the grace of God which is given me to you-ward: 3 How that by revelation he made known unto me the mystery; (as I wrote afore in few words, 4 Whereby, when ye read, ye may understand my knowledge in the mystery of Christ) 5 Which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit; 6 That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel: 7 Whereof I was made a minister, according to the gift of the grace of God given unto me by the effectual working of his power. 8 Unto me, who am less than the least of all saints, is this grace given, that I should preach among the Gentiles the unsearchable riches of Christ; 9 And to make all men see what is the fellowship of the mystery, which from the beginning of the world hath been hid in God, who created all things by Jesus Christ:

Understanding and respecting the differences between the church, the body of Christ, and Israel and their earthly kingdom gospel, is how one can easily see that there will be mortal beings living during Christ's millennial physical reign on earth. At some point after armageddon all things on earth and heaven (Israel, and us) will be joined together for eternity:

Ephesians 1:9-10

Having made known unto us the mystery of his will, according to his good pleasure which he hath purposed in himself: 10 That in the dispensation of the fulness of times he might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in him:

Answer 5

WHO will remain in perishable bodies (capable of reproducing) to repopulate the earth, thus producing the generations up to the final rebellion?

As a pre-Trib/pre-Mil dispensationalist, here is how I understand the future timeline.

• At some point, living Christians are raptured, along with the dead in Christ. This includes Jews who have accepted Christ during the church age. At that time we receive our immortal bodies and are forever with Christ.
• Then we get the seven year tribulation period (Matt. 24:21, etc.); at the end of which, there is a mass conversion of the Jewish people.
• Then Christ returns (Matt. 25:31), accompanied by the immortal Christians. There is a great battle and the beast, his minions, and the nations are defeated (Armegeddon; Acts 16:16; 19:11-21). Those who are alive on the earth at that time will be separated, as sheep and goats, to determine who gets to enter into the millennial kingdom. Those entering the kingdom will include believing Jews and those who are deemed righteous from the nations (Matt. 24:32-46).
• During the millennial kingdom, Christ will rule from the throne of David and immortal Christians will rule the nations. Folks will live for a long time, and babies will be born. Since Christ will be ruling with a rod of iron, and given that there are threats made against those nations which fail to bring in their tithe to Jerusalem, the implication is that the next generation will not automatically believe and submit to Christ's rule.
• At the end of the millennial period, the nations will rebel against Christ and are defeated (Gog & Magog; 20:7-10).
• The final judgment is subsequent to all of this (contra @DarkMalthorp)

I haven't covered the whole paradigm, but this is enough to frame up the answer: those who make it past the sheep and goats judgment are the mortals who repopulate the earth.

Answer 6

Although the question presupposes premillennialism and the Catholic Church, of which I am a member, currently holds amillennialism, I will still answer the question because premillennialism was indeed a valid position for Catholics during the first centuries after Christ, as it is the combination of the total number of the elect and the time elapsed between Jesus' Ascension and Second Coming which determines whether the Millennium of Rev 20:1-6 must be literal or can be symbolic. Because if the total number of the elect is very large, as implied by the size of New Jerusalem in Rev 21:16 (using the Egyptan stadium, each side is 12000 x 0.1575 = 1890 km long), and the time between Jesus' Ascension and Parousia is short, then it is necessary for many of the elect to come to exist that the Parousia be followed by an interval with a duration in the order of 1000 years (the "Millennium") during which the earth is populated by an aristocracy of resurrected saints in glorifed bodies - and therefore not able to sin, die or procreate - ruling with Christ (physically or spiritually present) over a majority of people in mortal bodies who will procreate and die after long lives.

Now, who comprise the part of the population of the earth in a state of mortal body at the beginning of the Millennium?

The answer starts by classifying the population of the earth at the end of the tribulation, i.e. at the time of the Parousia, in 3 groups:

1. The Christan faithful, who enter the Millenium in a state of glorifed body together with the resurrected martyrs.

2. The non-Christians of good-will (Karl Rahner's "anonymous Christians"), who enter the Millennium in a state of mortal body and whom the faithful in a state of glorifed body of group 1 will evangelize, catechize, administer the sacraments to, and shepherd, consistently with the end of Rev 20:6: "they will be priests of God and of Christ, and will reign with Him for a thousand years". The people of this group will procreate and die at the end of long lives (around 120 years?) and so on their descendants, until at the end of the Millennium many from the last generations will rebel and the Final Judgment will come.

3. The anti-christians, who die at the Parousia (Rev 19:21) and do not enter the Millennium.

If group 2 described above were theologically unacceptable, i.e. if it were not possible a middle state between groups 1 and 3 for people with use of reason, then group 2 could comprise unbaptized children that have not yet reached the use of reason. In that case the faithful in a state of glorifed body of group 1 would raise and educate them, in additon to evangelize, catechize, administer the sacraments to, and shepherd them.