5 Jesus answered, “I assure you: Unless someone is born of water and the Spirit, he cannot enter the kingdom of God.6 Whatever is born of the flesh is flesh, and whatever is born of the Spirit is spirit.7 Do not be amazed that I told you that you must be born again. 8The wind blows where it pleases, and you hear its sound, but you don’t know where it comes from or where it is going. So it is with everyone born of the Spirit.”
I don’t think “born of water:” here refers to baptism. It’s possible, but I think the verses that follow this statement help clarify the intent and meaning of verse 5.
I think born of water simply means “born naturally” or “born the way everyone is born.” That is to say, anyone hearing or reading these words was born the once. This we know for certain.
But Jesus states that simply being born the once does not usher you into the Kingdom of God any more than dying the once ushers you into His heavenly abode. We saw this theme first appear in the opening chapter of John’s Gospel if you recall where he pointed out that it is not those born of flesh, blood or the will of man that are children of God, but those that receive Jesus who are given the right to BECOME His children.
Verse 6 is simply a restatement of verse 5.
Born of water = born of the flesh
Born of the Spirit = born of Spirit.
Then Jesus says, “Don’t be amazed at this.”
God saves people.
He sends His Spirit to regenerate and rebirth people from the kingdom of death to the Kingdom of God. It has always been this way. This is not a new teaching. This is the way God saves people. No one who knows their Bible should be shocked by this repeating of revelation.