Let us meditate this Christmas morning on the sheer audacity of the idea that God would not only enter this world of time and misery, but come into it in the most humble manner possible, inter faeces et urinam nascimur, born between feces and urine, entering between the legs of a poor girl in a stable. Just like one of us, a slob like one of us. The notion is so mind-boggling that one is tempted to credit it for this very reason, for its affront to Reason, and to the natural man, accepting it because it is absurd, or else dismissing it as the height of absurdity. A third possibility is to accept it despite its being absurd, and a fourth is to argue that rational sense can be made of it. The conflict of these approaches, and of the positions within each, only serves to underscore the mind-boggling quality of the notion, a notion that to the eye and mind of faith is FACT.
The Most High freely lowers himself, accepting the indigence and misery of material existence, including a short temporal career that ends with the ultimate worldly failure: execution by the political authorities. And not a civilized Athenian execution by hemlock as was the fate of that other great teacher of humanity, but execution by the worst method the brutal Romans could devise, crucifixion.
In the Incarnation the Word nailed itself to the flesh in anticipation of later being nailed to the wood of the cross to suffer the ultimate fate of everything material and composite: dissolution. Christ dies like each of us will die, utterly, alone, abandoned. But then the mystery: He rises again. Is this the central conundrum of Christianity? He rises, but not as a pure spirit. He rises body and soul.
God is the Word ("In the beginning was the Word, and the Word was with God, and the Word WAS God"); the Word becomes flesh; the flesh nailed to wood becomes dead matter and nothing Wordly or Verbal or Logical or Spiritual or Sense Bearing, and so next-to-nothing; but then the next-to-nothing rises and ascends body and soul to the Father by the power of the Father. Christ rises bodily and ascends bodily. A strange idea: bodily ascension out of the entire spatio-temporal-bodily matrix! He ascends to the Father who is pure spirit. So, in ascending, Christ brings matter, albeit a transformed or transfigured matter, into the spiritual realm which must therefore be amenable to such materialization. It must permit it, be patient of it. The divine spiritual milieu cannot be essentially impervious to material penetration.
Before the creation and before the Incarnation of the Creator into the created order divine spirit had the power to manifest itself materially, and in the Incarnation the power not only to manifest itself materially but to become material. The divine Word becomes flesh; the Word does not merely manifest itself in a fleshly vehicle. It becomes that vehicle and comes to suffer the fate of all such vehicles, dissolution. The divine spirit was always already apt for materialization: it bore this possibility within it from the beginning. It was always already in some way disposed toward materialization. On the other hand, matter was always already apt for spiritualization.
We humans know from experience that we can in some measure spiritualize ourselves and indeed freely and by our own power. We know ourselves to be spiritual beings while also knowing ourselves to be animals, animated matter, necessarily dependent on inanimate matter including air, water, dead plants and dead meat. (When an animal eats another animal alive, the first is after the matter of the second, not after its being animated.)
Whether or not we exercise our severely limited power of self-spiritualization, we are spiritual animals whether we like it or not and whether we know it or not: we think. Each one of us is a hunk of thinking meat. We are meaning meat. How is this possible? The matter of physics cannot think. But we are thinking matter. This is the mystery of the entanglement of spirit and matter in us. We live it and we experience it.
We could call it the 'The Little Incarnation.' Mind is incarnated, enfleshed, in us. The Little Word, the Little Logos, has always already been incarnated is us, separating us as by an abyss from the rest of the animals. Here, in us, we have an ANALOGY to the Incarnation proper. In the latter, the Second Person of the Trinity does not take on a human body merely, but an individual human nature body and soul. So I speak of an analogy. Incarnation in the case of Christ is not a mere enfleshment or embodiment. The Little Incarnation in us is the apparently necessary enfleshment of our spiritual acts in animal flesh.
The mystery of the entanglement of spirit and matter in us reflects the mystery of the entanglement of spirit and matter in God. Divine spirit is pregnant with matter, and accepting of the risen matter of Christ, but matter is also pregnant with divine spirit. Mary is the mother of God. A material being gives birth to God. This is how the Word, who is God, is made flesh to dwell among us for our salvation from meaninglessness and abandonment to a material world that is merely material.
Matter in Mary is mater Dei. Matter in Mary is mother and matrix of the birth of God.
For a different take on the meaning of Christmas, see my Incarnation: A Mystical Approach?