John 3:3-6

3 Jesus replied to Nicodemus, "I can guarantee this truth: No one can see the kingdom of God without being born from above."
4 Nicodemus asked him, "How can anyone be born when he's an old man? He can't go back inside his mother a second time to be born, can he?"
5 Jesus answered Nicodemus, "I can guarantee this truth: No one can enter the kingdom of God without being born of water and the Spirit.
6 Flesh and blood give birth to flesh and blood, but the Spirit gives birth to things that are spiritual.