Christmas is coming! But the very idea that God --- whoever or whatever 'God' might be --- would become incarnate, human like us, seems quite beyond belief to many people today. Christmas, for most of us, is about shopping and parties, perhaps about Midnight Mass: anyway, a very familiar round of seasonal events; all too familiar, perhaps.
If by God we mean something like the force, the dynamic energy, that originates and sustains the utterly amazing universe which physics and astronomy and other sciences describe, then it seems quite unbelievable that it would or could ever actually be born as one of us, a human being, and specifically as the child of a Jewish woman, in a place, Bethlehem, and at a date more or less agreed by historians.
The date is only more or less certain because, as most experts now think, Dionysius Exiguus, the one who was called on in Rome in 533 or so to establish the Christian chronology, simply made a mistake: he chose 754 from the foundation of Rome as the first Year of the Lord; but, since Herod died in 750 and Jesus was born two years before that (see Matthew 2:16) Jesus must have been born in 4 B.C.
Even so, Jesus was certainly born in a particular place and time. The point that so many people find incredible is that God, granted what God must be if we are to regard the cosmos as having a divine creator at all, could ever become so specifically an item in human history. It simply seems outrageous, not just unexpected but quite preposterous.
By choosing these verses from Matthew for the First Sunday of Advent the Church certainly sides with the people who find the whole thing shockingly improbable. We are invited to see the birth of Christ as a 'coming of the Son of Man' --- Incarnation as 'advent', so to speak --- which is fine; but it is a coming like the flood in the days of Noah, surprising those who were eating and drinking, marrying and giving in marriage: they had no idea what was to hit them; more shockingly still, it is a coming like a thief breaking in during the night, when the owner of the house was asleep.
The lesson is, of course, that we need to be awake, not preoccupied with shopping, eating and drinking and party-going: watchful, waiting, expectantly, for something quite unprecedented, indeed something very disruptive; as cataclysmic as the flood which almost wiped out the human race, as unwelcome as the intrusion of a thief in the darkness of the night.
Of course there are other sides to the event, other images by which to make sense of it. Yet today the Church invites us Christians to remember just how overwhelming and subversive an event the birth of the child born to Mary actually is: if we were tempted to look forward to Christmas as shopping and parties and being safely at home with the television, then these images of flooding and invasion of privacy should be enough to de-familiarize us. If we are inclined to take the Incarnation for granted, as a familiar item among our Christian beliefs, then these disconcerting images should shake us out of our complacency.