John 3:1-21:

"There was a named Nicodemus, a Jewish religious leader who was a Pharisee.  After dark one evening, he came to speak with Jesus.  "Rabbi," he said, "we all know that God has sent you to teach us.  Your miraculous signs are evidence that God is with you."
Jesus replied, "I tell you the truth, unless you are born again, you cannot see the Kingdom of God."
"What do you mean?" exclaimed Nicodemus.  "How can an old man go back into his mother's womb and be born again?"
Jesus replied, "I assure you, no one can enter the Kingdom of God without being born of water and and the Spirit.  Humans can reproduce only human life, but the Holy Spirit gives birth to spiritual life.  So don't be surprised when I say, 'You must be born again.' The wind blows wherever it wants.  Just as you can hear the wind but can't tell where it comes from or where it is going, so you can't explain how people are born of the Spirit."
How are these things possible?" Nicodemus asked.
Jesus replied, "You are a respected Jewish teacher, and yet you don't understand these things? I assure you, we tell you what we know and have seen, and yet you won't believe our testimony.  But if you don't believe me when I tell you about earthly things, how can you possibly believe if I tell you heavenly things? No one has ever gone to heaven and returned.  But the Son of Man has come down from heaven.  And as Moses lifted up the bronze snake on a pole in the wilderness, so the Son of Man must be lifted up, so that everyone who believes in him will have eternal life.
For this is how God loved the world: He gave his one and only Son, so that everyone who believes in him will not perish but have eternal life.  God sent his Son into the world not to judge the world, but to save the world through him.
There is no judgment against anyone who believes in him.  But anyone who does not believe in him has already been judged for not believing in God's one and only Son.  And the judgment is based on this fact: God's light came into the world, but people loved the darkness more than the light, for their actions were evil.  All who do evil hate the light and refuse to go near it for fear their sins will be exposed.  But those who do what is right come to the light so others can see that they are doing what God wants."