"3 Now there was a man of the Pharisees named Nicodemus, a ruler of the Jews. 2 This man came to Jesus by night and said to him, “Rabbi, we know that you are a teacher come from God, for no one can do these signs that you do unless God is with him.” 3 Jesus answered him, “Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God.”4 Nicodemus said to him, “How can a man be born when he is old? Can he enter a second time into his mother's womb and be born?” 5 Jesus answered, “Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. 6 That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. 7 Do not marvel that I said to you, ‘You must be born again.’ 8 The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit.”
John 3:1-8
Two further points must be noted here before we pass to the next verses. The first is that Nicodemus' words in 4 seem to indicate that he was an elderly man. Bishop Ryle says this is something that should make us understand and appreciate the slowness with which age adapts to new opinions and new ideas, but it is also an encouraging proof that no one is too old to be converted. The second point relates to the words 'water' and 'spirit'. Interpretation here falls into two schools of thought: there are those who believe that 'water' refers to baptism, and there are those who believe it does not. Among the latter are numbered Bishop Ryle and Calvin, and the general view they hold is that the phrase 'water and spirit' simply refers to regeneration by the Word and Spirit of God, and that it is analogous to that other word of Jesus when He spoke of being baptised with the Holy Spirit and with fire. To refer it to baptism in the sense that regeneration is by baptism is simply to make nonsense of the general teaching of the Scriptures. As Ryle points out, Jesus goes on to rebuke Nicodemus for not knowing these things (10). But regeneration by baptism is nowhere spoken of in the Old Testament Scriptures, and Nicodemus could hardly be rebuked for not knowing something that he could have no opportunity of knowing. There may, however, be an even simpler explanation: it is that 'water' refers to John the Baptist's ministry and to his baptism of water. Jesus would then mean, as Temple puts it: 'The first step needed is openly to become an adherent of John's revival, the mission of repentance, in which has sounded after so long a time the authentic word of prophecy. That first; but that is not enough, then openly join this company among whom the powers of the new birth, the new life, is moving'. This is how the first disciples came into the kingdom. First John's water baptism, then the baptism of the Spirit. So it must be with Nicodemus – that is, he must come the same way as the others.