The Bible offers a number of details about the birth of Jesus, but it's mum on the exact date.

Sometime in the fourth century, Pope Julius I officially decided on Dec. 25.

That date made perfect sense: What better time to celebrate the coming of the "The Light of the World" than in the darkness of winter?

More recent generations of Christians have preserved in song this image of light piercing the dark. And in my mind, no hymn or Christmas carol better captures the momentousness of that first Christmas in Bethlehem than "O Holy Night."

From its "stars brightly shining" to its "new and glorious morn," this poem-set-to-music illuminates the incarnation - God becoming human - and the promise of salvation.

The song's words are more welcome than ever on this Christmas Day, when Christians exult in God's shining gift of himself to a world longing yet again for the dawn of a new day.

At times, 2010 has felt like one long night, with old wars and threats of new ones, with too few jobs and too much fear, with angry speech and anxious hearts.

But today, as families gather, giving gifts and singing carols, followers of Jesus are invited to let go of their worries and embrace a joy that comes not from dwelling on bad headlines but from believing in what Christians call the Good News.

French carol translated

That's not always easy to do, especially when dark clouds hover.

In 1855, with America on the brink of civil war over the sin of slavery, abolitionist John Sullivan Dwight's search for that divine light led him to write an English translation of a French Christmas carol and rename it "O Holy Night."

A Boston-born, Harvard-educated Unitarian minister, Dwight was especially moved by a line in the song's third verse that portrayed Jesus as the chain-busting liberator of the slave, "our brother."

Dwight's life was infused with music. He had married a singer, spent much of his time studying Beethoven and, in 1852, founded Dwight's Journal of Music, which became an influential publication in mid-19th century America.

A literal English translation of "Cantique de Noël," the French carol, has little of the poetic majesty of Dwight's enhanced version. Instead of adopting the literal translation that Jesus descended to earth to erase the stain of original sin and end the wrath of God the father, performers of Dwight's translation sing:

"O Holy Night, the stars are brightly shining.

It is the night of the dear Savior's birth.

Long lay the world, in sin and error pining,

Till he appeared and the soul felt its worth."

Like a Christian theology lesson set to verse, the words from Dwight cast Christmas as the event in human history when God became flesh. Entering the world as a helpless baby, raised by humble parents, he would go on to show the world how to live in love and, by his supreme sacrifice, would rescue God's children from the doom of sin.

"A thrill of hope," the carol continues, " the weary world rejoices,

For yonder breaks a new and glorious morn!"

Making broadcast history

The lyrics and the soft-then-soaring music of "O Holy Night" grew so popular that, just after the start of the 20th century, it would become part of broadcasting lore.

The way chemist Reginald Fessenden told it, his scratchy violin rendition of the carol on Christmas Eve 1906 was the second song ever sent through the air via radio waves. The first was a recording from Handel that Fessenden played the same night.

As the story goes, the world's first radio transmission of voice and music was beamed from a shack at Brant Rock, near Boston, to United Fruit Company ships in the Atlantic Ocean and Caribbean Sea.

Picking up his violin, Fessenden played "O Holy Night." By the time he got to the uplifting final verse, about Jesus' call to action, Fessenden was singing as well as playing:

"Truly he taught us to love one another.

His law is love and his gospel is peace ..."

The forgotten second verse

On this Christmas Day 2010, "O Holy Night" is on many a holiday playlist. On my iPhone, I can listen to renditions by Nat King Cole, Luciano Pavarotti and Martina McBride.

The second verse, with its references to "the light of faith serenely beaming," "glowing hearts" and "the light of a star sweetly gleaming," isn't heard much these days. It's a victim, in my view, of the slick, get-to-the-point commercialism that threatens even religious Christmas music.

But like me, many do know the song's chorus by heart, so stirring and so familiar is its call on Christians to respond with delight and gratitude to God's radiant gift to this hurting, yet still hopeful world:

"Fall on your knees,
O hear the angel voices.
O night divine,
O night when Christ was born;
O night divine, O night, O night divine."