You quoted the verse: "one who is born of the flesh must also be born of the spirit in order to see, enter and inherit the kingdom of God," Taken that literary - if you are not born of the Spirit - you dont go to Heaven - rather you go to Hell.
So does this apply to babies
I do not see heaven in contrast to hell anywhere in John 3. It just states one must be born of the spirit to see and or enter the kingdom of God.
Is it about the kingdom of God or is it about heaven and hell [Hades]?
Question. Is the kingdom of God of John 3 the same kingdom of God that 1 Cor 15:50 states flesh ans blood cannot inherit?
Is that the same kingdom of God Abraham, Isaac, Jacob and others will sit down in of Luke 13:28,29
Matt 25:34 Then shall the King say unto them on his right hand,
Come, ye blessed of my Father,
inherit the kingdom prepared for you from the foundation of the world:
When do you think Abraham, Isaac and Jacob will inherit the kingdom?
Lets talk about David.
'Men, Israelites! hear these words, Jesus the Nazarene, a man approved of God among you by mighty works, and wonders, and signs, that God did through him in the midst of you, according as also ye yourselves have known; this one, by the determinate counsel and foreknowledge of God, being given out, having taken by lawless hands, having crucified -- ye did slay; whom God did raise up, having loosed the pains of the death, because it was not possible for him to be held by it, for David saith in regard to him: I foresaw the Lord always before me -- because He is on my right hand -- that I may not be moved; because of this was my heart cheered, and my tongue was glad, and yet -- my flesh also shall rest on hope, because
Thou wilt not leave my soul to hades,
nor wilt Thou give Thy Kind One to see corruption; Thou didst make known to me ways of life, Thou shalt fill me with joy with Thy countenance. Acts 2:22-28
Who is the prophet David speaking of there? ----- Jesus the Nazarene ----- Not himself. ------ What does Peter say concerning David?
V 29 'Men, brethren! it is permitted to speak with freedom unto you concerning the patriarch David, that he both
died and was buried, and his tomb is among us unto this day; And Acts 13:36 says he saw corruption...
On Pentecost 50 days after the weekly sabbath following the death of Jesus the Nazarene Peter says the soul of David was in dead in Hades and his flesh had seen corruption. David went to his baby son and in order to inherit the kingdom of God both will need to be born again. John 3:7 Marvel not that I said unto thee, Ye must be born again. He also went to his fathers Abraham, Isaac and Jacob Acts 13:36 For David, after he had served his own generation by the will of God, fell on sleep, and was laid unto his fathers, and saw corruption:
IMHO that is what the word of God states.
I do believe the baby of David will be in the kingdom of God. According to mercy and grace of God.