REST NOW, ye merry gentlemen - Fox News commentator Bill O'Reilly says he has defeated the "forces of darkness" that supposedly were waging a "War on Christmas."

When underpaid and underinsured cashiers sell you stuff you can't afford to give to people who don't really need it, much of it made in deplorable conditions overseas, they will be sure to wish you a "Merry Christmas" instead of that sinister "Happy Holidays."

"Every company in America should be on its knees thanking Jesus for being born," O'Reilly said two Christmases ago when he discovered the "war" that nobody else had noticed. "Without Christmas, most American businesses would be far less profitable." And O'Reilly doesn't want rich or poor, man or woman, gentile or Jew to forget it.

Too bad nobody noticed we were losing in the War on Advent. Then again, Advent has never turned a profit.

Old-timers may recall that, back when Christmas was a religious holiday, the four weeks of Advent was the time when many Christians prepared their hearts for the birth of Jesus. Back then, the first Sunday of Advent used to be the official beginning of the Christmas season - before it was replaced by another religious ritual, Black Friday.

Advent was a time of penance and fasting. It's why many traditional ethnic Christmas Eve celebrations - oyster stew for the Irish, "seven fishes" for Italians, pierogis for Eastern Europeans - are meatless. Of course, modern Christmas preparation also includes hardship, not to mention degradation. Shoppers wear themselves out spending that $435 billion we're expected to drop on Christmas this year. And what mortification could compare to the prostrations of desperate parents seeking this year's Big Gift?

Advent was a time of great expectation, anticipation and hope. Kids and grown-ups lit candles on Advent wreaths and counted off the days of an Advent calendar. These days, surveys show that many Americans count down to Christmas not with anticipation but with dread. Google "Christmas" and find scores of warnings - from psychologists about "holiday depression," from financial advisors about the massive debt we'll incur, and from law enforcement with tips to escape the seasonal increase in crime.

During Advent, Christians traditionally read verses from Psalms and the prophets. These days, it can be hard to hear Jesus' message over all the din, much less proclaim it.

An organization called Catholics in Alliance for the Common Good found that out when it recently placed ads calling for a "cease-fire in the culture wars."

"We believe the real assault on Christmas is how a season of peace, forgiveness and goodwill has been sidelined by a focus on excessive consumerism," the group said. "The powerful message Christ brings to the world is 'good news for the poor.' Instead, Christmas is being reduced to a corporate-sponsored holiday that idolizes commerce and materialism."

Them's fightin' words. Last week, O'Reilly challenged the group's president, Alexia Kelley, for calling his rhetoric "divisive," apparently considering his "war" rhetoric as the path to togetherness. He called Kelley "naïve," and seemed to really freak out whenever she tried to say the word "universal."

"You would have lost the Christmas fight," he fumed, "because the secularists don't care about Christmas. All they want to do is get Christianity - Catholicism, Protestantism, whatever it may be - out of the public square."

To that, this secularist pleads guilty. No religion should be in the public square, not even when the overwhelming majority of citizens practice it. Besides, the big boxes and malls make it impossible to miss the fact that it's Christmas.

Wouldn't it be something if they wished us a "meaningful Advent," asked us how the preparation of our hearts was going, and sneaked in a Psalm verse between "Jingle Bell Rock" and "Little Drummer Boy"?

Counting today, there are 13 more days of Advent. I wouldn't dare speak for all "secularists," but I wouldn't mind being bombarded with messages of peace, forgiveness and our obligations to the poor from now until Dec. 25. It surely would trump the mall-to-mall crowds, the soulless advertising, the bad music and bad values.

Just maybe, it would focus our attention on the churches, homes and families where the real Christmas still thrives.

Praying with the News: Let us pray for the British teacher threatened with whipping and even death in Sudan for allowing her students to name a teddy bear Mohammed. May her story remind us once again why the separation of church and state must be absolute. *

Carol Towarnicky was a long-time member of the Daily News editorial board. E-mail