Jesus was always conscious of His audience and of time and timing in His ministry. So consider the setting of His meeting with Nicodemus, recounted in John 3:1-21. It is at the very beginning of His ministry, and He is meeting with one of the top Jewish religious leaders. What would Jesus want to say to him?
I would argue that Jesus would want to tell him important things that he didn’t already know. Thus, there is no need to tell a top Jewish leader that a monotheistic God exists, or that he should love God and love his neighbor, or about the Ten Commandments and the rest of the Torah and the prophets, because Nicodemus would have known all that; what’s more, Nicodemus in particular acknowledges at the outset (verse 2) that Jesus is “from God” and that God is “with him.” But what are the important things that the Jewish establishment did not know? What is new in Jesus’ Good News?
Three things, I would argue: (1) that internal impurities have to be removed from us humans just as surely as external impurities do; (2) that God’s message is universal and that He wants to save not just Jews but Gentiles as well; and (3) that there is eternal life.
And, I would argue finally, I think that these are indeed the three points that Jesus makes to Nicodemus.
Footnote: I hasten to add that none of these points is a retraction of what Jews believed or inconsistent with it, but I really don’t think there is any doubt that with Jesus and Christianity we have a pivot, a clarification, a new point of emphasis — call them what you like. To elaborate just briefly on each of the three points: Very early in the Sermon of the Mount, Jesus stresses the importance of what is now often called “heart posture” (see Matthew 5:21-30); in the next chapter, Jesus will deliver the gospel to a Samaritan woman and, in the Great Commission (28:19), Jesus enjoins Christians to “go and make disciples of all nations,” as Paul and the rest of the early church surely did (see Acts); and regarding eternal life, recall that the Sadducees, in particular, did not believe in that, and that apparently even other Jews did not have the reality of Heaven and Hell before them — not much of either in the Old Testament or in Judaism then or today, is there, compared especially with Christianity and the New Testament? [Addendum: Here’s N.T. Wright’s take on afterlife in the Old Testament.]
Here is the text of John 3:1-21:
1 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!” 5 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.”
9 “How can this be?” Nicodemus asked. 10 “You are Israel’s teacher,” said Jesus, “and do you not understand these things? 11 Very truly I tell you, we speak of what we know, and we testify to what we have seen, but still you people do not accept our testimony. 12 I have spoken to you of earthly things and you do not believe; how then will you believe if I speak of heavenly things?
13 No one has ever gone into heaven except the one who came from heaven—the Son of Man.14 Just as Moses lifted up the snake in the wilderness, so the Son of Man must be lifted up, 15 that everyone who believes may have eternal life in him.” 16 For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. 17 For God did not send his Son into the world to condemn the world, but to save the world through him. 18 Whoever believes in him is not condemned, but whoever does not believe stands condemned already because they have not believed in the name of God’s one and only Son. 19 This is the verdict: Light has come into the world, but people loved darkness instead of light because their deeds were evil. 20 Everyone who does evil hates the light, and will not come into the light for fear that their deeds will be exposed. 21 But whoever lives by the truth comes into the light, so that it may be seen plainly that what they have done has been done in the sight of God.
I’ll acknowledge that I’ve divided the verses into paragraphs in a way that best helps make my point, but I’ll add that I think this is the best division anyhow. Verses 1 and 2 set the stage and establish that Jesus knew that He need not spend much time persuading Nicodemus of His godliness. Then (1) verses 3-8 are about being born again in the Spirit (and in water, as opposed to just flesh), which I would suggest — admittedly, it’s not crystal clear — are about the need for internal as well as external purity, for purity of heart as well as purity of action; (2) in verses 9-12, as well as in subsequent verses, Jesus signals or says that the Jews now need to acknowledge their own limits as uniquely chosen, since God and His love for humanity is universal; and (3) in verses 13-21, God promises eternal life to those who believe in His Son, who has come to save us — and, conversely, that those who do not so believe will be condemned (note that this is stated as a universal rule, with no Jew-Gentile distinction).