v1-2: Nicodemus was an important man, a member of the Sanhedrin. He came to Jesus secretly, by night, fearing the response and opinion of others. It seems they met in a house rather than in the street. Later, Nicodemus began to support Christ (7.50-51), and then to identify with Him (19.39).

Nicodemus spoke in the plural, "we" being unwilling to avoid personal interest in Christ, yet he was somehow drawn to Him. In response, Jesus spoke to an individual of his need, for Nicodemus was alone. Jesus also did not consider all Pharisees and religious leaders to be hypocrites.

Nicodemus spoke of signs, as in 2.23, but Jesus spoke of salvation. He moved the discussion from conversation to commitment. It is striking to think of a respected member of the Sanhedrin meeting with an itinerant preacher from Galilee; but Jesus is not uncomfortable in the presence of anyone; He remains dignified in His manner, and uncompromising in His message.

The narrative suggests an eye-witness, probably John himself, who was of a priestly family. Under the guidance of God’s Spirit, he adds his explanation in v16-21; compare also his additions in v31-36, following the description of the ministry of John Baptist.

v3-4: You must be born again; the essential message. Jesus rarely used the word "must" but there is no other way to enter the kingdom of God. Peter used "must" in Acts 4.12, urging his listeners to trust in Christ for themselves.

The phrase "born again" is not common, and seems to be more appropriate for religious people, of especially Jewish people, who tend to trust in their own religion. A Gentile was ‘new born’ when he became a Jewish proselyte, and so Nicodemus would have been familiar with the phrase itself.

What Nicodemus would have struggled with was the phrase “born from above” (margin), which is something spiritual. Nicodemus, a religious man, could not understand what Jesus  meant. Here was something new for him.  The new birth, or conversion (referring to the same experience) is God’s work, see 1.12-13; 1 Cor 2.12,14; Eph 2.8-9. It is something altogether different from a Gentile becoming a Jewish proselyte

v5-6: New birth is different from natural birth, 1 Cor 15.44. The phrase "born of water" may refer to natural birth, or possibly to baptism as a Jew, as John had practised. Here is a new and essential dimension of life, knowing God in a real and special way. To be “born of the Spirit” is something only found in Jesus Christ; it is something He does (see 1.33).

'Flash gives birth to flesh, but the Spirit gvies birth to spirit.' Such is the contrast between natural birth and re-birth. The converted person is new, totally changed. Much of what Paul writes, for example, in Romans, assumes this truth. We are now 'in Christ,' and 'raised with Christ.'

v7-8: The new birth is a spiritual work of God in the life, something naturally impossible. The new birth does not mean we cease to be the same human being. The person, the morally accountable self, remains. There is continuity, otherwise the concepts of forgiveness and cleansing woud be irrelevant. (See John Piper, Finally Alive, chapter 2)

v9: Nicodemus lacked understanding. We do not need to ascend into heaven to discover spiritual truth, for the Son of Man has come down from Heaven.

v10: Jesus did not mock Nicodemus, but His words indicate the spiritual poverty and ignorance prevalent in Israel at the time. If we do not know the essentials of the life of Christ, then other matters are irrelevant.

v11-13: The Son's authority, speaking of earthly things and of heavenly things. He has come down from Heaven, bringing the unique message of God. He uses the title Son of Man, of Himself. His origin, however, is Heaven not the earth.

v14: Jesus looked forward to His suffering; O.T. types and prophecies must be fulfilled, the bronze serpent was just one of many such types. Jewish readers would appreciate the significance of such words, and Nicodemus would have been familiar with the particular incident.

v15: Jesus used the O.T. picture to encourage faith; the message for the many, "everyone who believes," the message to deliver from death into life, the message of faith and trust. If being born again is God's work, then believing in Christ is something we must do.

v16: The new issue; God's love; this love is demonstrated in Jesus Christ, sent from Heaven, sent to die for us, being lifted up that we might have life. William Tyndale’s translation is helpful here; “God so loved the world that He gave His only Son for the intent that none that believe in Him should perish.”

God could give nothing better; Matt 21.37 indicates that, for Israel, this was a last opportunity; the Son could do something no prophet could do, bring an inheritance, even life itself.

God's love is now for all the world, not just restricted to Israel, if it ever was.

Without accepting God's Son, Jesus Christ, we perish, in this life, and in the next. A life lived outside of faith in Christ is a life destined to perishing, a downward spiral of self-interest, and no hope.

John Maynard Keynes, economist, not a believer, said; ‘It has yet to be proved that profound transformation in our world is possible without seeing the truth of the God who so loved the world that He was generous and gave His only Son to die upon the cross to love the loveless into loving.’

v17: Jesus' own words to Nicodemus appear to end in v15; verses 16-21 are John's comment on Jesus' words.

Christ came to save, not to judge; see Luke 4.18-19, where He omits the reference to God's vengeance in Is 61.1-2. Condemnation will come, at the right time. But now is the day of salvation.

v18: Unbelief, rather than sins, leads to condemnation; this is consistent with Rom 4, for god justifies the ungodly by faith.

Faith must be in Christ. Rejection of Christ is rejection of God, and therefore loss of life.

v19: The verdict, or decision, or judgment, of God; that men prefer darkness, for their deeds are evil. Natural man prefers his life of sin. All this is in spite of the fact that God has shone His perfect light, Jesus Christ, into this world.

v20: Sin is reproved by God's word; people shun the word because it exposes their sins.

v21: The believing man; he does the truth, he obeys, living a life of good works. He comes to the light, willing to be examined by God, that he grow in his obedience. See Ps 119.5-6, where the psalmist comes to the word; where he comes with steadfast ways, he comes without shame.

v22: Jesus with His disciples, as in 2.2,12; He spent some time with them. Many who came to Him were baptised (only John mentions this).

Jesus Himself baptised no-one, see 4.2, He came to baptise with the Holy Spirit (1.33). See also 1 Cor 1.13-17, where the issue of who baptised whom caused difficulties at Corinth. We note that Jesus' ministry was therefore different from His followers'.

v23-24: John continued to preach and baptise, 4.1 mentions this as well. This was apparently not the best situation, and caused some conflict. This conflict only ceased when John was imprisoned.

v25-26: The dispute between John's disciples and some Jews. This became a pretext for the Jews to try to put a barrier between John and Jesus; compare Matt 11.16-19; wisdom is justified by her children. Jesus made no public criticism of John, although he seems to have continued his ministry for too long, once Jesus was working publicly.

v27-30: John's reply;

• re-stating, "I am not the Christ," although sent by God;
• as the friend of the bridegroom, he was full of joy at Christ's coming;
• his joy is complete; should his ministry also have been complete?
• He was prepared to decrease, that Christ might increase; all John's followers should have become Jesus' followers, as in 1.35-37.

v31: Christ, "from above," unique and exalted, different from John. John is "from the earth" and "born of woman" (Matt 11.11).

v32: John and Christ both testified, and were both rejected. Christ spoke of the things of Heaven and eternity, things that He had seen. See also 5.19.

v33: Christ's message, that God is true, and to be trusted.

v34: God has sent Christ; in Him the Holy Spirit moved without restriction. Similarly, the Holy Spirit enables us to testify concerning Christ.

v35: Christ's authority; all things are in His hands.

v36: Test of true faith, whether or a not a person believes in Jesus Christ, see also v16-18.