John 3:3

There was a man of the Pharisees, named Nicodemus, a ruler of the Jews:

The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him.

Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?

Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.