Are there two classes of the saved in God's Kingdom?
The teaching that anyone goes to heaven other than Jesus Christ is a false doctrine not found in the Bible.
John 3:13 And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven.
The purpose of God in creating the earth is for it to be inhabited and filled with his glory.
Isaiah 45:18 For thus saith the LORD that created the heavens; God himself that formed the earth and made it; he hath established it, he created it not in vain, he formed it to be inhabited: I am the LORD; and there is none else.
Numbers 14:21 But as truly as I live, all the earth shall be filled with the glory of the LORD.
This glory is to be in the form of men and women made equal unto the angels and given immortality.
Luke 20:35 But they which shall be accounted worthy to obtain that world, and the resurrection from the dead, neither marry, nor are given in marriage: 36 Neither can they die any more: for they are equal unto the angels; and are the children of God, being the children of the resurrection.
We do not possess an immortal soul or spirit which continues in a conscious existence after death.
Ecclesiastes 9:5 For the living know that they shall die: but the dead know not any thing,
Psalms 146:4 His breath goeth forth, he returneth to his earth; in that very day his thoughts perish.
When we die, we ‘sleep’ in the dust awaiting the day of Christ’s return to raise and judge the dead, and give the faithful eternal life in the kingdom of God.
Daniel 12:2 And many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt.
John 5:28 Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, 29 And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation.
The kingdom of God will be the restored kingdom of David upon the earth.
Luke 1:32 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
Jesus will reign over the mortal population of the earth from Jerusalem for 1000 years.
Isaiah 2:1 The word that Isaiah the son of Amoz saw concerning Judah and Jerusalem. 2 And it shall come to pass in the last days, that the mountain of the LORD’S house shall be established in the top of the mountains, and shall be exalted above the hills; and all nations shall flow unto it. 3 And many people shall go and say, Come ye, and let us go up to the mountain of the LORD, to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the LORD from Jerusalem. 4 And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more.
Revelation 20:6 Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years.
The salvation through Jesus Christ comes via the promise made to Abraham of an eternal inheritance upon the earth through his seed.
Genesis 13:14 And the LORD said unto Abram, after that Lot was separated from him, Lift up now thine eyes, and look from the place where thou art northward, and southward, and eastward, and westward: 15 For all the land which thou seest, to thee will I give it, and to thy seed for ever. 16 And I will make thy seed as the dust of the earth: so that if a man can number the dust of the earth, then shall thy seed also be numbered. 17 Arise, walk through the land in the length of it and in the breadth of it; for I will give it unto thee.
Genesis 22:18 And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.
Galatians 3:16 Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ…18 For if the inheritance be of the law, it is no more of promise: but God gave it to Abraham by promise. 28 There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus. 29 And if ye be Christ’s, then are ye Abraham’s seed, and heirs according to the promise.
God’s promise through Abraham and Christ is eternal inheritance on the earth. Abraham received no inheritance in his lifetime and must be raised from the dead to inherit the promise.
Psalms 37:9 For evildoers shall be cut off: but those that wait upon the LORD, they shall inherit the earth.
Psalms 37:11 But the meek shall inherit the earth; and shall delight themselves in the abundance of peace.
Psalms 37:22 For such as be blessed of him shall inherit the earth; and they that be cursed of him shall be cut off.
Matthew 5:5 Blessed are the meek: for they shall inherit the earth.
After the millennial reign of Christ there will be a second resurrection and final judgment. Those rejected will die again (the second death) and all who live on will possess the divine nature.
2 Peter 1:4 Whereby are given unto us exceeding great and precious promises: that by these ye might be partakers of the divine nature, having escaped the corruption that is in the world through lust.
God will dwell with, and in, his people in the kingdom of God upon the earth.
Paul explains what is to happen:
1 Corinthians 15:20 But now is Christ risen from the dead, and become the firstfruits of them that slept. 21 For since by man came death, by man came also the resurrection of the dead. 22 For as in Adam all die, even so in Christ shall all be made alive. 23 But every man in his own order: Christ the firstfruits; afterward they that are Christ’s at his coming. 24 Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power. 25 For he must reign, till he hath put all enemies under his feet. 26 The last enemy that shall be destroyed is death. 27 For he hath put all things under his feet. But when he saith all things are put under him, it is manifest that he is excepted, which did put all things under him. 28 And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all.
From this we see that following the millennial reign and final judgment, sin and death will be no more. The earth will be restored to its former glory. Christ will be subject to his Father and God will be ‘all in all’ and dwell with man for eternity.
This is described in Revelation.
Revelation 21:3 And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God. 4 And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away.
I hope you find this helpful.