Why Celebrate Christ's Birth, Instead of His Conception?

Since life begins at conception, why do we focus on celebrating the Birth of Christ, rather than His Conception?  After all, from a Catholic perspective, the Incarnation really occurs about nine months prior to Christmas.  Indeed, pro-life movements around the world have begun using March 25 as a day celebrating the life of the unborn, during the Feast of the Annunciation, nine months before Christmas.  And why do we pro-lifers throw birthday parties, instead of conception-day parties?  Why do we speak of being born again? Why measure our ages from the date of our birth, instead of conception?

I. The Conception and Birth of Christ

Agnolo Bronzino, Adoration of the Shepherds (c. 1538) (detail)

LifeSiteNews has a great article fittingly called, “If life begins at conception, why wouldn’t we celebrate the Incarnation instead of Christmas?”  That's a rather reasonable question, and LSN does a good job answering it:

To be sure, the Incarnation is celebrated in many churches, including the Roman Catholic Church and the Eastern rites, on March 25th, quite appropriately nine months ahead of Christmas. But while the Incarnation (also known as the Annunciation) is observed in such cases as a great feast, it’s certainly not afforded the solemnity and pomp of Christmas.

And that’s the way it should be, I’d say.

Conception is hidden, private, intimate. When a couple realizes they have conceived a child, they are naturally filled with joy, but that joy is held between them.

As they reveal the happy news to family and friends, or the child makes herself known by the mother’s blossoming belly, the child’s presence is revealed more and more until she is ready to declare herself to the world.

While our joy at the conception of a child is often no less than at her birth, it is usually less conscious. It takes time for this amazing gift to strike us.

So, quite naturally, we reserve our greatest celebrations for the child’s birth.

Georges de la Tour, Adoration of the Shepherds (1644)

This is a very good answer, and one which finds plenty of support in early Christian writings.  For example, St. Fulgentius of Ruspe described Christmas as the day that “our King, clothed in His robe of flesh, left His place in the virgin’s womb and graciously visited the world.”  This description makes it clear that Christ was very much alive in the womb before Christmas, but that He wasn't really in the world yet.  

Likewise, Scripture puts a strong emphasis on the circumstances of the birth of Christ (Lk. 2:1-20), while we know basically nothing about the time and place of His conception (Gabriel prophesies it in Lk. 1:35, but we don't even know how quickly that prophesy came true).  Nevertheless, Scripture is quite clear that Christ is alive prior to His birth (as well as John the Baptist: see Lk. 1:39-45, and here).

II. Was Christ Eternally Begotten?

There's a great parallel to all of this in a dispute from the early Church.  The Arians denied that God the Son was eternally begotten of the Father.  Instead, they claimed that Christ became the Son at His Baptism, and pointed to passages like Psalm 2:7, Acts 13:33, Heb. 1:5, and Heb. 5:5 for support.  This heresy has had a resurgence amongst some Evangelicals; even John Armstrong used to teach it.

1st Council of Nicea - Arius is in brown

This heresy may seem like a minor quibble, but it's not.  If Jesus wasn't always the Son of God, then the core teaching of orthodox Christianity, the Trinity, is wrong.  But the Arians were wrong, and the First Council of Nicea (325 A.D.) condemned them for it.  The First Council of Constantinople (381 A.D.) built on Nicea by adding a phrase to the Nicene Creed explaining that Christ is eternally-begotten, or “begotten of the Father before all worlds.” (For good measure, jolly old St. Nicholas actually slapped Arius in the face for denying the Divinity of Christ).

The reason that we can say that the Arians were heretics is that well before His Baptism, Christ affirms His unique Sonship; this is clearest in Luke 2:49, in which a young Jesus speaks of going about His Father's business.  This is about two decades before His Baptism, yet He's already the Son of the Father in a unique way.  Indeed, throughout every statement He ever makes about the Father, Jesus calls the Father “My Father” or “your Father,” but never “Our Father,” to make clear to us that He's the Son of the Father in a way that we aren't (see, e.g., John 20:17).  We're adopted as sons and daughters of God (Romans 8:17), but Christ is the Only-Begotten (John 3:16)

And St. John begins His Gospel with this beautiful insight into the Trinity, and particularly of the relationship between the Father and the Son (John 1:1-3):

Andrea del Verrocchio, Baptism of Christ (1475)

In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things came into being through Him, and apart from Him nothing came into being that has come into being. 

So Jesus doesn't become the Son of God at His Baptism, or even at His Birth.  He's the Son of God for all eternity, from “the beginning,” which is why God can speak of Himself in plural form clear back in Genesis 1:26.  

So what's going on with those passages which would seem to suggest He was begotten at His Baptism?  At His Baptism, what was hidden to the world (that the Son of God was among them) was made visible: that's the sense in which Hebrews and Acts say that Jesus is “begotten” at His Baptism.  But He was the Son of God before this, from all eternity.  Likewise, Christmas celebrates the point at which what was hidden to the world (that the Son of Mary was among us) was made visible.  But Jesus was the Son of Mary before this, from about nine months earlier.

So just as we might say that Jesus was twelve years old when He went up to the Temple (Luke 2:42), measured from His birth, without literally suggesting that He didn't exist prior to His birth, we see something similar in the way Scripture speaks of His Baptism.

Conclusion

The image that I think captures this well is of a gift under a Christmas tree.  The gift is already there, and if you receive it in the mail, you already own that gift prior to unwrapping it.  But the celebration is of the moment that you unwrap it, and encounter it in a certain way for the first time.

Certain things are totally private, and conception is one of them (even parents don't know the exact moment of conception -- there's something mysterious and beautiful about the fact that it's known to God alone).  We may get excited at seeing the wrapped presents placed under the tree, knowing what they herald.  But we quite reasonably celebrate the point at which the presents are unwrapped,  and we come face to face with the Gift.