Supposedly genteel Episcopalians putting each other down; Roman Catholics nursing wounds from the sex-abuse scandal; Christians of various stripes disputing noisily over the war in Iraq and the nature of matrimony -- hmmmm. More peace and good will, no doubt, as ordered up by the angelic host.

Christianity's origins, whenever they arise in conversation, sometimes make Christians attentively examine their shoelaces, hoping the indicated question will not arise: If Christianity is so wonderful and life-changing a thing, what is wrong so much of the time with Christians themselves? What kind of walking billboards are they for Little Lord Jesus, asleep in the hay?

The Spanish Inquisition often comes up in conversations of this sort and of course slavery and the alleged oppression of minorities. There are grunts of disgust when "fundamentalist" interference with "science" or "the separation of church and state" gets an airing.

The history of Christianity, it sometimes seems, is an unholy mess -- apart from those instances of holiness and beauty that transfigure life, just not often enough for some.

The key point to keep in mind is the circumstance of the birth at Bethlehem. Now what in the world (or out of it) must the creator of heaven and earth (a k a God) have thought He was up to, pulling off such an improbable event in a backwater province of the Roman Empire? What was the purpose here? You know, the marketing strategy?

The written testimony of the early church has to be weighed. The angel spoke of a "savior," born in the City of David. Saviors are no small potatoes. This was no rescue party sent out from the Roman barracks in Jerusalem, with a clatter of horses and spears. This was heavenly intervention -- very large potatoes indeed. That was because, by the common account of the succeeding centuries, there was this troubling factor in human affairs called Sin, which was to be redressed through the birth and the death of the Son of God in human form.

It was the matter of sin that embarrassed then and embarrasses now. Sin implies fault, shortcoming. What, us? Short in the virtue department? Somehow we weren't quite ... nice? That couldn't be it. Of course we were nice! Didn't we help out at home, pay our taxes on demand and hold our cutlery just so?

In truth, the defect implied by the coming of the Lord in human form was more basic: Our human nature was bent, like an overburdened clothing rod. More than smiles and politeness and observance of duty would be necessary to fix it. And, in earthly terms, it really could not be "fixed," not just yet. Faith in the Little Lord Jesus was a sound step in the short run, but it would take his resurrection and return to dispose once and for all of the "bentness" problem.

In the meantime, Christians would be ... people. Of a certain sort, naturally. But, still, people. Not always "nice" to others, not even nice, all the time, to fellow Christians. This was notwithstanding the commandment of the Babe, grown to manhood, that they should "love one another," as he had loved them. They would try. But -- sigh -- bentness often would block the way.

Over the centuries, the physical achievements of Christianity -- the hospitals, schools, universities and missions -- as well as the deeds of mercy, forbearance and sacrifice would surpass all logical expectation. At their very best, the people of the manger -- Christians -- would speak of themselves as the redeemed, bearing a message of redemption "which shall be to all people."

The stumbles along the way, the falls, the catastrophes, would remind them of the human mess over which the angels hovered on that silent night: not in approval or confirmation, rather, in love of the wayward humans into whose midst a savior had come. To whom, that is, Christmas had come.