In the Catholic world, all monks and nuns (and friars and sisters) vow three things: poverty, chastity, and obedience.

In a vernacular version: no money, no honey, and a boss.

It’s a tradition going back at least to the fall of Rome. Without these vows, monastic life would lose its soul. Materially speaking, it would be impracticable.

And yet.

I have been vowed to chastity for almost a decade now, and it has become a way of life, but I must admit: the time when celibacy seems strangest is Christmas.

(Christmas. You may have heard of it. It’s a holiday when Christians celebrate the event that, in our view, irrevocably changed the universe. Michael Wex tells me that, in American Yiddish slang, Christmas is called Krats-mikh, scratch me. Perhaps that helps.)

Christmas is a children’s holiday, albeit not only that. One remembers standing as a preschooler in front of the big nativity scene to the side of the altar in church. Mary and Joseph and the whole menagerie had stood for days gazing at an empty wooden box with straw in it, but now the baby Jesus had plopped in in a painted diaper. Merry Christmas.

No children, though, in the monastery.

That’s a good thing, maybe. In the days leading up to the holiday, the hallways of our priory would be unsafe for tender tots. It looks like the night before a battle: huge floor polishers – one so large you ride it like a mule – come out to wax the checkerboard floors. Long ladders enable young monkey-monks to climb up to forgotten windowsills under the vaults and dust the top of the hanging placard screaming “Silentium!” over the main corridor.

In Poland, not a squeaky-clean country, Christmas and Easter are two stimuli that never fail to make people whack things into (temporary) shape.

Then there’s the church. Secular Scandinavia this ain’t. On Christmas eve at midnight, our huge fourteenth-century basilica will be as crowded as a Tokyo train. People bring camp stools to sit on, since there are never any pews left. As the liturgy glides on slowly in the cold night, the peaks of the arches in the nave become obscured by a cloud of warm breath. We don’t heat the church on Christmas — the faithful do it for us.

This afternoon, a large carpet was rolled out in the sanctuary to mark the place where the amateur orchestra will sit. A harpsichord and harp were wheeled in yesterday, under shrouds and shock cords. Wooden risers have been built for a volunteer chorus of about 80 young people. These eager legions have been practicing Polish equivalents of “Joy to the World” and “Silent Night” for a month. You can hear them doing tongue-twisting warm-ups at rehearsals in the afternoons, getting ready to tackle Slavic church-speak confections like “Zbawiciel” (Savior) and “zdumienie” (awe).

Poles pray with fervor on Christmas night, and the flake-frosted facades outside and ecstatic musical confessions within the church accompany them in their yearning. The ineffable is tangible. Heaven is ready to soak through a permeable membrane and transfuse our clammy world.

That, really, is what Incarnation means. The transcendent becomes immanent, and a Child is born.

And yet, in this monastery, no children are born. And as the monks eat together, at the long refectory tables, the canonical treat of carp in aspic (i.e., Christmas gefilte fish), one does sense their absence. One is merry, but perhaps not entirely so.

As I sit and munch the fish, I sometimes wonder: why do we live this way?

And the only possible answer is: because this is not all that there is. On Christmas, and on any day, the lives of monks make sense only within the frame of eternity. Only if there is a God are we anything but crackpots in robes. Only if there is a life after this is it possible to live, even now, exclusively with God.

And then I remember what happened on this night. On Christmas, God broke through a membrane and plopped out, warm and wet, on the cold ground south of Jerusalem. Scandalous, but there it is.

On Christmas night it should be easy to believe that God is nigh.