After JESUS told Nicodemus (in John 3:1-10) that he must be born again to have ETERNAL LIFE, HE continued by saying,
11- Very truly I tell you, we speak of what we know, and we testify to what we have seen, but still you people do not accept our testimony.
12- I have spoken to you of earthly things and you do not believe; how then will you believe if I speak of heavenly things?
13- No one has ever gone into heaven except THE ONE WHO came from heaven—THE SON OF MAN.
14- Just as Moses lifted up the snake in the wilderness, so THE SON OF MAN must be lifted up,