I LOVED THEM ALL, the hymns we sang in our red brick Methodist church on Christmas Eve. There was always snow, it never failed us, and the streetlamps cast lovely pools of light and shadow on the shoveled walks. We called it midnight service, though it actually began an hour earlier; we would have eaten our dinner and opened our presents. The men in our family stayed home. I loved all the Christmas hymns, but one of them was magic.

I’ve since learned that it was another of those marvelous Victorians (The OED! The Dictionary of National Biography! Where would we be without them?) to whom we owe the English verses. In its original Latin, Veni Veni Emmanuel was a product of the medieval monastery, dating back to the twelfth century at the very latest. John Mason Neale discovered the verses in the appendix of an eighteenth-century manuscript and published them, in English, in his Mediaeval Hymns and Sequences (1851). Three years later, in The Hymnal Noted, Thomas Helmore paired them with a melody he claimed to have found in “a French missal in the National Library, Lisbon.” That missal has never been relocated, but in 1966 the musicologist (and Augustinian canoness) Mary Berry discovered the same melody in a fifteenth-century manuscript in the Bibliothèque Nationale. The English hymn celebrates a longed-for birth, so I find it rather poignant to learn that this tune, at least in its fifteenth-century incarnation, served as a processional chant for burials.

But then, the hymn I love has always been a mixture of celebration and mourning:

O come, O come, Emmanuel,
And ransom captive Israel,
That mourns in lonely exile here
Until the Son of God appear.

Rejoice! Rejoice! Emmanuel
Shall come to thee, O Israel.

As witness to its mingled joy and sorrow, the hymn is set in a minor key.

I knew nothing of its history, of course, when I sang this hymn with all the good people who filled the pews of the Cary Methodist Church on Christmas Eve. I doubt I knew what Emmanuel meant, and I didn’t think to wonder. I only knew—I took it in somehow with the very first chords of the organ prelude—that we were welcoming a mystery. Number 211 in the Methodist hymnal, key of E minor: E is where the hymn comes home, and minor keys are good for mystery.

In the Book of Isaiah, the prophesied messiah is called Emmanuel. In the Book of Matthew, an angel tells Joseph that his betrothed is the virgin of the prophecy, her child the child of God. Emmanuel, as the evangelist is careful to specify, means “God with us.” There is sweetness in the minor chord: discovering what he had taken to be her shame, Joseph had planned to put Mary aside “privily.” Joseph is a just man.

Above the altar in our red brick church was a single stained-glass window, very small, circular, depicting the Holy Ghost in the form of a bird. Our one gesture toward ostentation. In the heat of the English Reformation, the Puritan Richard Baxter used to rail against the “painted obscure sermons” of the Anglican preachers, pronouncing them to be no better than “the Painted Glass in the Windows that keep out the Light.” I had never heard of Richard Baxter when I lived in Cary, Illinois; I’d barely heard of the Reformation. No one had ever preached to me about the dangers of idolatry. But the stained-glass windows in the Roman Catholic Church on the other side of town, like the bleak dormitories for the nuns, struck me as slightly sinister. The priest lived in a fine new house.

It was only by accident, really, that we were Methodists at all. Norwegian immigrants belonged to the church of Luther. But when my grandparents moved from Chicago in the 1920s, our small town had only one Protestant church on offer, and it was the church of John Wesley. My grandfather was a fine craftsman, meticulous in his pinstriped overalls. It was he who, on a windless day, climbed the steeple to apply gold leafing to the cross. Modest ostentation: a plain gold cross on a plain white steeple, upright in praise, and the overalls freshly ironed. Women did that then. The windows in the nave were tall and broad, with panes of transparent glass.

So it’s ironic, really—it quite betrays me—to realize that I must have loved this hymn for its whiff of the monastery: chalice and incense smuggled in by way of the minor chord. There’s a moment, a breathtaking moment, when the meter defies expectation. Everything has been steady-as-you-go, four-four time, all quarter notes and dotted halves. But during that remarkable refrain, just when you expect to dwell on the last syllable of the holy name for a count of three, as every verse before this has prepared you to do, the hymn leaps forward and anticipates itself by half a measure. No breath, no stately pause: Emmanuel / Shall come to thee, as though rushing to arrival. Those missed beats never fail to stop my heart.

And they rhyme somehow with the promise and foreboding built into that second long era of expectation, the one believers inhabit now, because the child so fervently awaited has come and been killed and has promised to come again. Two women shall be grinding at the mill; the one shall be taken, and the other left. The minor chords of a hymn sung toward midnight in a small town blanketed by snow. He shall come like a bridegroom; he shall come like a thief in the night. And when we least expect it, the leap across a missing half-measure.

In a poem, or a painting, or a stage play, it’s the rarest and most wonderful of all effects, to be taken by surprise, even when you know the surprise is coming. Repeatable surprise. It shouldn’t be possible. It requires something more than double awareness or divided consciousness: it requires authentic inhabitation of two non-commensurate states of expectation. I suppose in this it is like faith. I don’t believe in hell. I don’t believe in the afterlife, except perhaps in the hearts of those who love us. But the promise of a savior in a minor key and the promise of judgment in those dark gospel verses—dark good news—never fail to seize my heart.

Linda Gregerson’s most recent book of poetry is Prodigal: New and Selected Poems (Houghton Mifflin Harcourt). She teaches creative writing and Renaissance literature at the University of Michigan.

This essay and the eight that accompany it in our issue will appear as part of Stars Shall Bend Their Voices: Poets’ Favorite Hymns and Spiritual Songs, edited by Jeffrey Johnson and forthcoming this fall from Orison Books.