Take a gander at John 3:3-5:
Jesus answered and said to him, “Amen, amen, I say to you, no one can see the kingdom of God without being born from above.”
Nicodemus said to him, “How can a person once grown old be born again? Surely he cannot reenter his mother’s womb and be born again, can he?”
Jesus answered, “Amen, amen, I say to you, no one can enter the kingdom of God without being born of water and Spirit."
The term "born of water" refers to water Baptism. Water Baptism, therefore, according to Jesus, is a normatively necessary condition for salvation.
NO IT DOES NOT
And he never told Nick to go get immersed.
He said "3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God."
He said "5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.
He said 6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
He said 7 Marvel not that I said unto thee, Ye must be born again.
He said 8 The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit.
And Nick asked him... 9 Nicodemus answered and said unto him, How can these things be?
He said 10 Jesus answered and said unto him, Art thou a master of Israel, and knowest not these things?
Jesus knew very well that it would have been abundantly obvious to Nicodemus, a teacher of all Israel, that Jesus was surly plainly speaking of
tevillah, or mikvah, or what Christians call baptism. And Jesus knew that
Nicodemus would know that the Mikvah (a ritual pool of water, used for the purpose of attaining ritual purity).
"Immersion" in connection with Repentance and to remove the impurity of sin. Also for Conversion.. and as such Jesus would have been clearer. Nicodemus, after all was looking for a conversion of sorts.
Jesus could easily have said to start there..... but he didn't
What Jesus was referring to was what we have learned from Ezekiel 36: 25-27... for this is what Nicodemus as
a master of Israel would have known.
25Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you. 26A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you an heart of flesh. 27And I will put my spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do them.
A new spirit born again with the Spirit God.