We have a newborn at home. I've been thinking a lot about Dr. Harvey Karp's idea of the
"fourth trimester": the brain cannot complete its development prior to birth, because if it did, the baby's head wouldn't fit through the birth canal. Or, alternatively, according to some researchers, because human brain development needs to occur in the context of hearing speech and observing the environment. In either case, human infants are uniquely helpless among mammals: a newborn foal, for instance, will start walking within hours, whereas for neurological reasons, a newborn human cannot.
God, on the other hand is omnipotent, impassible, and characterized by aseity: almighty, not prone to harm or suffering of any kind, and utterly, utterly independent. God as He Is in Himself could not suffer, and could not die. To suffer and die for us, St. Athanasius explains in his classic On the Incarnation, God had to take mortal flesh. Only we mortals can suffer and die.
At the nativity, God Almighty was born as a "fourth trimester" human infant: the most helpless of all the mammals. From limitless power, invulnerability to suffering, and complete independence, Our Creator was born a tiny creature powerless, oh so fragile, and completely, helplessly dependent upon His Mother.
The Third Joyful Mystery of the Rosary is the Nativity, in which we pray for the virtue of being Poor in Spirit. And what greater poverty of spirit could there be than this--to surrender power over for the whole whirling cosmos for powerlessness, to surrender invulnerability for fragility, to surrender painlessness for pain, to surrender independence for helplessness, to surrender the form of God to put on the form of a slave?
Christ told the rich young man to give away all he had to the poor. This was no idle bit of sanctimony. Jesus Christ, God in suffering flesh, knows more than any of us can ever fathom what it is to have all the cosmos, and surrender it all. To give away infinite riches, and be poor and helpless as only a human infant can be. He did this. For you. Merry Christmas!