John 3:3-6 — Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God. 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. That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.

There is a process in the Christian life that I’m trying to understand. It’s the idea that we must be born again, and that we must become as little children if we are to enter the kingdom of heaven. It is the process, if you like, that expands the truth that if any man is in Christ he is a new creation …
The process was made possible when Jesus entered the world as a little baby. His rebirth, his advent, has become for me a picture of an “advent” we must all undergo as we become what God has made us to be.
Jesus describes this “advent” to Nicodemus at their meeting that is recounted in John 3. I don’t think Nicodemus is the only one to find Jesus’s words difficult. In fact, two thousand years later, I think most of us find them cryptic the first time we hear them. Thomas Merton the twentieth century Trappist monk and spiritualist explains it brilliantly in his book “Rebirth and the New Man in Christianity”:

What Jesus speaks of is a new kind of birth. It is a birth which gives definitive meaning to life. The first birth, of the body, is a preparation for the second birth, the spiritual awakening of mind and heart. … The rebirth of which Christ speaks is not a single event but a continuous dynamic of inner renewal.

Charles Wesley built the rebirth into his most famous (and perhaps most scriptural) Christmas carol:

Hail, the heaven-born Prince of peace!
Hail the Son of righteousness!
Light and life to all he brings,
Risen with healing in his wings.
Mild he lays his glory by,
Born that man no more may die,
Born to raise the sons of earth,
Born to give them second birth.
Hark! the herald angels sing,
Glory to the newborn King.
(Hark The Herald Angels Sing)

Passing through our second birth we can make our advent, our entry into the new creation. We can shed the worldly “adulthood” that we may have grown up into and begin our spiritual childhood.
The second birth, like the first, may be traumatic and painful — but oh the glorious new life we are born into!