Nicodemus was a leader and a Pharisee. He came to Jesus at night because he probably did not want the other Jewish leaders to know about the visit. Nicodemus readily admits that he believes that Jesus has been sent from God. He wants to know more about this man that is proclaiming that the kingdom of God is near. Jesus immediately tells Nicodemus that unless you are born again, you will never see the kingdom of God. What an amazing concept! How can a human be born again? Jesus explains that He is not talking about physical rebirth, but spiritual. It is not a physical change, but a change of the desires of the heart. How does this happen? From a human standpoint, we are unable to explain what happens inside. But just as the wind comes and goes without our understanding, so the Holy Spirit works inside us to renew us and rebirth us as children of God. We may not know how, but the work that He does in our hearts leaves no doubt in our minds that we are being made into new creatures. At the very moment that we accept Jesus as our Savior and Lord, the new creation is born with all the rights that come with being a citizen of heaven. God will spend a lifetime completing the work that He has started in us, but finish it, He will.
1 Therefore we also, since we are surrounded by so great a cloud of witnesses, let us lay aside every weight, and the sin which so easily ensnares us, and let us run with endurance the race that is set before us, 2 looking unto Jesus, the author and finisher of our faith,—Hebrews 12:1-2a (NKJV)