Cross reference
John 4:11
11 The woman said to him, Sir, you have no vessel and the fountain is deep; from where will you get the living water?
John 3:4
4 Nicodemus said to him, How is it possible for a man to be given birth when he is old? Is he able to go into his mother's body a second time and come to birth again?
1 Corinthians 2:14
14 For the natural man is not able to take in the things of the Spirit of God: for they seem foolish to him, and he is not able to have knowledge of them, because such knowledge comes only through the Spirit.