Then why does the Lord go on about the heavenly kingdom? Perhaps He was chastening Nicodemus for not understanding that the suffering servant would come before the conquering King.
John 3:11-13 Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness. If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you of heavenly things? 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 heavenly things concernes an individual being born of God, being born again. Therefore, the citizenship of those who are born again is in heaven. Now concerning the earthly thing, beginning at John 3:3 the Lord had been speaking of an individual's regeneration but He now begins to speak of the nation of Israel's regeneration. The Lord shifts from using the second person "singular" pronoun "you" to the second person "plural":
"You should not be surprised at my saying, 'You must be born again. The wind blows wherever it pleases. You hear its sound, but you cannot tell where it comes from or where it is going. So it is with everyone born of the Spirit" (Jn.3:7-8).
Nicodemus still did not understand, asking,
"How can these things be?"
By the Lord's reply we can understand that Nicodemus should have been aware of some truth in the OT Scriptures which spoke of a regeneration by the Spirit:
"Art thou a teacher of Israel, and knoweth not these things?" (v.10).
Nicodemus should have been aware of a prophecy that speaks of the corporate regeneration of Israel. Here we see that prophecy of that regeneration which speaks of the "wind" and of the "spirit":
"Then said he unto me, Prophesy unto the wind, prophesy, son of man, and say to the wind, Thus saith the Lord GOD; Come from the four winds, O breath, and breathe upon these slain, that they may live. So I prophesied as he commanded me, and the breath came into them, and they lived, and stood up upon their feet, an exceeding great army....And shall put my spirit in you, and ye shall live, and I shall place you in your own land: then shall ye know that I the LORD have spoken it, and performed it, saith the LORD" (Ez.37:9-10,14).
This is the earthly thing of which the Lord Jesus spoke and Nicodemus should have been aware.
If your ideas are correct then Peter must have placed an entirely different meaning on the words "born again" than did the Lord Jesus. And if you are correct then the words 'born of the Spirit" mean something other than the words "born of God." That is because we know that people were born of God in the past when they believed the gospel.
Can you give me one verse where anyone in the Bible using the words being "born of the Spirit" to refer to anyone putting on a glorious body like the lord Jesus' glorious body?