Nicodemus, a highly esteemed religious teacher, went to see Jesus. Jesus told him plainly, “Very truly I tell you, no one can see the kingdom of God unless they are born again.” This perplexed Nicodemus. Obviously no on can be physically born a second time! What could Jesus mean?
Jesus explained that unless a person is born “of the Spirit” he can never participate in God’s kingdom. In his explanation, Jesus drew a comparison between something Nicodemus knew, and something he didn’t know. Nicodemus knew the Old Testament. Jesus referenced the story of Moses and the snake. Just as Moses had to lift up the snake on a pole, so Jesus himself would have to be lifted up (i.e. crucified).
John tells us that this is all because God loves the world so much that he sent Jesus to provide for our salvation.