John 3: 1-8, Nicodemus Visits at Night

The author, the disciple John, includes in his gospel lots of small private events that the other gospels do not.  This passage begins with a private meeting between Jesus and a Jewish religious leader, Nicodemus.

John 3: 1-8, Jesus teaches Nicodemus
Now there was a Pharisee, a man named Nicodemus who was a member of the Jewish ruling council. 
2 He came to Jesus at night and said, “Rabbi, we know that you are a teacher who has come from God. For no one could perform the signs you are doing if God were not with him.”

3 Jesus replied, “Very truly I tell you, no one can see the kingdom of God unless they are born again.”

4 “How can someone be born when they are old?” Nicodemus asked. “Surely they cannot enter a second time into their mother’s womb to be born!”

Nicodemus has high standing in the religious community. He is curious about this radical, Jesus, and so seeks Jesus out "at night", presumably to keep the meeting secret. Nicodemus begins the conversation with praise, mentioning the "signs" Jesus has done. (The gospel writer has, at this point, not provided us with any public signs other than the cleansing of the temple.  But John, the writer, intends for his readers to already know about Jesus' Galilean ministry from the other gospels.)

Jesus takes advantage of the praise of Nicodemus to emphasize the importance of a spiritual (re)birth. This spiritual birth is very different from the bloody physical birth. It is initiated by the Holy Spirit in keeping with the prophesy of Ezekiel 36: 26-27.

But Nicodemus does not understand the metaphor.

John 3: 5-8, Second birth
Jesus answered, “Very truly I tell you, no one can enter the kingdom of God unless they are born of water and the Spirit. 
6 Flesh gives birth to flesh, but the Spirit gives birth to spirit. 
7 You should not be surprised at my saying, ‘You must be born again.’ 
8 The wind blows wherever it pleases. You hear its sound, but you cannot tell where it comes from or where it is going. So it is with everyone born of the Spirit."

Although commentators may differ (depending on other theological views), one natural reading in verse 5 is to identify "born of water" as the physical birth we all have, breaking out of the amniotic sac. If that is the meaning of "born of water", then verse 6 gives a parallel: there are two births, one physical, one spiritual.  Nicodemus should expect to be spiritually born also.  In verse 7 Jesus challenges Nicodemus, as a religious leader, to understand this and not be so shocked.

The baptism of John was intended to emphasize this -- it asked people who were already Jews to go through the bathing ritual required of people converting into Judaism. It asked people to declare that they were taking a spiritual step to be spiritual Jews. (Because of this, some commentators read "born of water" as meaning "baptized", as in "baptized by John.")

Verse 8 is, to me, somewhat strange. Here Jesus says that the spiritual birth is just like the wind, something one might hear but not see.

The phrase "born again" could also be translated "born from above", says the NIV footnotes.