7 You should not be surprised at my saying, ‘You must be born again.’ 8 The wind blows wherever it pleases. You hear its sound, but you cannot tell where it comes from or where it is going. So it is with everyone born of the Spirit.” 9 “How can this be?” Nicodemus asked. 10 “You are Israel’s teacher,” said Jesus, “and do you not understand these things? 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, 15 that everyone who believes may have eternal life in him.”
Nicodemus’ question tells us he is still uncertain about who Jesus is and what his mission is. Is he a prophet or the Messiah? I believe Nicodemus wanted our Lord to explain his mission and thereby resolve the question. Instead, he reveals an astonishing truth; one must be born again in a spiritual birth by water and the spirit. In addressing the question, Jesus opens up a whole new world to Nicodemus. It is true for us too, and for anyone who willingly lets himself or herself to be led by divine grace and the gifts of the Holy Spirit. These are infused at baptism and enhanced through the sacraments.
The Spirit opens up our souls to God. Additionally, we Christians need to keep selfish appetites at bay and our inclinations to pride. If one is to understand the lessons God is trying to teach our soul, that soul must be stripped of everything created. This stripping includes our ego or self-will. It includes our achievements and our abilities, our understanding of the world, and even feelings we have. When all that is unlike God is cast out, the soul may receive the likeness of God, nothing will remain in it that is not the will of God, and it will thus be transformed in God. (St. John of the Cross, Ascent of Mount Carmel, book 2 chapter 5).