Jesus answered him, I assure you, most solemnly I tell you, that unless a person is born again (anew, from above), he cannot ever see (know, be acquainted with, and experience) the kingdom of God.
Nicodemus said to Him, How can a man be born when he is old? Can he enter his mother's womb again and be born?
Jesus answered, I assure you, most solemnly I tell you, unless a man is born of water and [even] the Spirit, he cannot [ever] enter the kingdom of God. [Ezek. 36:25-27.]
What is born of [from] the flesh is flesh [of the physical is physical]; and what is born of the Spirit is spirit.
Marvel not [do not be surprised, astonished] at My telling you, You must all be born anew (from above).
The wind blows (breathes) where it wills; and though you hear its sound, yet you neither know where it comes from nor where it is going. So it is with everyone who is born of the Spirit.
Nicodemus answered by asking, How can all this be possible?
Jesus replied, Are you the teacher of Israel, and yet do not know nor understand these things? [Are they strange to you?]
I assure you, most solemnly I tell you, We speak only of what we know [we know absolutely what we are talking about]; we have actually seen what we are testifying to [we were eyewitnesses of it]. And still you do not receive our testimony [you reject and refuse our evidence–that of Myself and of all those who are born of the Spirit].
If I have told you of things that happen right here on the earth and yet none of you believes Me, how can you believe (trust Me, adhere to Me, rely on Me) if I tell you of heavenly things?