John 3:3,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.” 

The word “born” is Strong’s Greek word G1080, “genná?,” and should here be translated “begotten.” 

“I say to you, unless one is begotten again, he cannot see (perceive or comprehend) the kingdom of God.” We cannot comprehend the Kingdom of God unless we are begotten of the spirit. 1 Corinthians 2:14 (NASB), “But a natural person does not accept the things of the Spirit of God, for they are foolishness to him; and he cannot understand them, because they are spiritually discerned.” 

John 3:4, “Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother’s womb, and be born?” 

Nicodemus displayed a certain naiveness in his questions. He was speaking from a natural standpoint. Jesus did not respond to the perspective Nicodemus was presenting.

John 3:5, “Jesus answered, Verily, verily, I say unto thee, Except a man be born (begotten) of water and of the Spirit, he cannot enter into the kingdom of God.” 

Jesus answered that to enter the Kingdom of God, a person needs to be born (begotten) of water and of the Spirit. We are begotten of “water,” which symbolizes the truth of accepting Jesus as savior. John 4:10 (NKJV), “Jesus answered and said to her, ‘If you knew the gift of God, and who it is who says to you, ‘Give Me a drink,’ you would have asked Him, and He would have given you living water.” The Apostle James wrote that God “Of his own will begat he us with the word of truth, that we should be a kind of firstfruits of his creatures.”James  1:18 (KJV)

(While we encourage water baptism, this scripture is not teaching water baptism as necessary to salvation.)

John 3:6, “That which is born (genná?) of the flesh is flesh; and that which is born (genná?) of the Spirit is spirit.” 

Strong’s Greek word G1080, “genná?,” may also be correctly translated as “born.” 

This verse applies both to fleshly and spirit begettal/birth. Jesus was conceived of flesh when he was implanted in Mary. Then he was born in the flesh nine months later. Jesus was begotten of the Spirit at his baptism and born a spirit being at his resurrection. Hence, Jesus became a spirit.

John 3:7-8, “Do not marvel that I said to you, 'You must be born again.’ The wind blows where it wishes, and you hear the sound of it, but cannot tell where it comes from and where it goes. So is everyone who is born of the Spirit.” 

The wind is an invisible power. Even though we cannot see it, we can hear it wail and see it breeze through trees. Yet the wind itself is invisible. Thus we can know of the existence of something, even if we cannot see it. Christians who are born of the Spirit are also invisible to the human eye, yet they exist.