3 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
Nicodemus was someone we might call a "seeker". He saw the signs (miracles) Jesus was doing and he was curious. Just who was this Jesus? Could he be the Messiah who was long hoped for? So Nicodemus goes to Jesus at night for fear that he might be found out.
Nicodemus acknowledges that Jesus could not perform these signs unless he came from God. So Jesus jumps in and says, "no one can see the kingdom of God unless they are born again." Nicodemus is not getting it, he is thinking only in terms of physical birth.
But then Jesus tries to link the signs he is doing with the kingdom of God. He wants to teach Nicodemus that he can do these things because he is born from above. He had a mom too, Mary. But he was also born from above, as was publicly evidenced when he was baptized, and the Spirit descended upon him like a dove. Nicodemus is trying to understand the signs Jesus did from a human perspective, but Jesus is teaching him that these signs are an evidence that the kingdom has come. And it had come through him. To believe in Jesus would give Nicodemus new birth as a son of God and entrance into the kingdom of God.
What does this mean? When we come to believe in Jesus as the Christ, the Messiah, we become a new creation. Just as when were physically born, we were a new creation in our parent's lives. When we are born again, we are born into God's family. We have become children of God. And our lives take on a whole new meaning, as a result of a whole new relationship with God. The Holy Spirit is God's gift to us to bring us into this new life. In fact we can't become born-again unless the Holy Spirit brings us to faith in Jesus. The Spirit gives us new life and gives birth to our spirit, which is why we enter into a new relationship with God. No longer are we in fear of God, but we call him "abba", which means daddy.
Do you feel a sense of God's Spirit in your life? Or maybe you had that sense of God working in your life but then for various reasons you have drifted from your relationship with God? Or maybe there are things in your life that are preventing you from experiencing God's presence like unconfessed sin. And remember we all sin so there is no shame in that. The Holy Spirit convicts us for our sin so we can ask for forgiveness and be renewed. But the Spirit does not bring condemnation and shame. The Spirit says "come home to God, he loves you." Just as the Father welcomed the prodigal son back home, God is always there waiting for us to come back to him.
Nicodemus later came to be born-again and entered God's kingdom through believing in Jesus. At Jesus' burial he and Joseph of Arimathea, were the ones who brought spices to embalm Jesus and prepare him for a proper burial.