Christmas,” Swiss theologian Hans Urs Von Balthasar wrote, “is not an event within history but is rather the invasion of time by eternity.” By this he meant that the Christmas event was not limited to a particular moment or even an epoch, but signaled an unfolding apart from the limitations of time. The improbability of eternity disrupting time itself is the principal upending in the long list of unexpected reversals that characterize the Christmas story.

Startling events set that story in motion: a young woman of no special social standing is visited by an angel, and in short order the virgin is pregnant. Her betrothed, who, according to custom and religious law, has every right to send her away or have her executed, instead goes through with the marriage. Underneath a star so bright it is visible in daylight, the couple travels to another city and finds not a single room available for the mother of the Son of God. Thus, the Messiah is born and laid in a manger, a trough reserved for animal feed.

It’s very strange, a series of incongruities. Underscoring all of them is the notion that God would want anything to do with humanity. This, Søren Kierkegaard writes, is the core absurdity of Christianity itself: