According to tradition, Mary gave birth to Jesus at the place of where the star is located on the floor. The tradition that the birth was in a cave is one of the oldest Christian traditions. Justin Martyr mentions it in the mid-2nd century, as does the Protoevangelium of James (also 2nd c.). Origen notes that the cave of Jesus' birth was pointed out in his day and no doubt this was the same place where the Byzantine church was erected.
From Crisis Magazine
by Rev. James V. Schall SJ.
I once read of a Japanese writer who was annoyed that Christ had not appeared in some inn in the hills of Honshu. The logic of this complaint would mean that, to satisfy everyone’s sense of justice, Christ would have to appear in every place. He could not have been born just once in one place. Put that way, we see a certain logic in His being born in one place and one time. As it turns out, the choice of one place and of one time points to the importance of all places and all times.
On Christmas, we talk of Christ’s actual birth from Mary, His mother. Life, of course, begins at conception, not birth. The Annunciation, accordingly, has always been celebrated on March 25. Christ’s birth is but the carrying forward of a plan that commenced long before even His conception. So when, at Christmas, I speak of its “place,” I mean something closer to the intelligibility of the Christmas event. On the surface, it is intelligible enough as the birth long ago of a human child in a far-off land. But the Christmas hymn is right to ask: “What child is this?”
St. Cyril of Jerusalem (+386) wrote:
We do not preach only one coming of Christ, but a second as well, much more glorious than the first. The first coming was marked by patience; the second will bring the crown of a divine kingdom. In general, what relates to our Lord Jesus Christ has two aspects. There is a birth from God before the ages, and a birth from a virgin at the fullness of time. There is a hidden coming, like that of rain on fleece, and a coming before all eyes, still in the future.
The birth “before all ages” and the birth “in the fullness of time” concern the same Being, as does His “second coming.” An order, a plan is found in these births and comings. The birth of Christ in this world is not simply fortuitous.
Cyril emphasizes that Christ came “in the fullness of time” (Eph., 1:10). Christ is “born of woman,” lest any doubt be had about His humanity. This affirmation that God could become man for many, even up this very day, was and is a stumbling-block, something that supposedly could not happen. Christian theology has long sought to show that, however astonishing, the Incarnation is not contradictory. And if it is not contradictory, it might well happen, granted a reason for it. That reason for God’s becoming man is provided by the “place” of Christmas. Christ is called, “Emmanuel,” God with us.This is what He is named.
Christ has also been called “the humanity of God.” He is “God with a human face.” Nevertheless, what was born of Mary was not a human but a divine Person. His origins are not in her but in the Trinitarian life of the Godhead. This Person did not come to be at the moment of human birth. He existed from eternity. He dwelt “amongst us.” What Mary makes possible is the free acceptance of the divine plan from the human side. God did not become man by “imposing” Himself on mankind. He was, as it were, invited: “Be it done unto me according to thy word,” Mary responds to the Angel.
Modern culture has made great efforts to obfuscate our understanding of Christmas. It has evaporated the heart of the event while pretending to keep its trappings. The White House has decided to call its decorative pines “Holiday” not “Christmas” trees. Why? we might wonder. It is because “Christmas” means something definite. Of course, even the word “holiday” means “holy day.” Still, it is a form of blasphemy to celebrate Christmas when nothing transcendent is acknowledged to celebrate. Christmas still reveals souls, even in high places.
What is important about Christmas is a fact. This fact is that God was born into this world at a certain time and place. The world cannot be what it is without recognizing this fact: that what has origins in eternity, in “the fullness of time,” came to dwell amongst us. We can and are making every effort to eradicate this fact from our perception. But it will not go away. Without Christmas, our world has no meaning but what we give to it. Yet, Christmas remains at the heart of the world, the place where the glory of the Lord dwells.
Catholicism Pure & Simple 