So what happened? Why are many churches in the U.S. booming? Why is Christianity expanding so rapidly in Africa and China? To begin to answer that, we should let our imaginations run wild: What if in the 20th century, in the biggest country by land area and also in the biggest country by population, leaders had required the teaching of atheism in all schools? Freed of "feeble-minded inventions," wouldn't the world be a better place?

Oh, you say we don't have to imagine? You say the Soviet Union and China did establish atheism and the results were not pretty? Atheists regularly write about the ravages of the Inquisition. Sure: It appears that the Inquisition over the centuries killed 5,000 people, which in my view is 5,000 too many. But Stalin and Mao killed not 5,000 or 50,000 or 500,000 or 5 million, but at least 50 million. Torturing and killing innocent people is a human phenomenon, not a religious one. There's plenty of sin to go around.

Keeping that Soviet and Chinese experience in mind, it's remarkable that Christopher Hitchens, author of "God Is Not Great," claims his fellow atheists "may differ on many things, but what we respect is free inquiry, openmindedness, and pursuit of ideas for their own sake." Who is "we"? Hitchens writes that atheists who disagree on a question "resolve it by evidence and reasoning and not by mutual excommunication." But the 20th century was a century of atheists resolving their disputes not by excommunication, but by murdering each other.

Hitchens argues that biblical commands lead Christians to two conclusions: either "a continual scourging and mortification of the flesh," along with confessions of guilt and denunciation of others, or "organized hypocrisy," with churchgoers paying the religious authorities to give them a break. He offers two alternatives: a "spiritual police state" or a "spiritual banana republic."

But the advent of Christmas offers a third alternative: grace. John Newton, the author of the hymn "Amazing Grace," had been a slave trader. He became a Christian, finally realized the evil he had done and could fight with confidence against slavery, despite his past, because he knew his sins were forgiven.

The atheistic best-sellers often lump together all religions, but Christianity differs from other religions in its emphasis on grace. Lots of religions are bargaining opportunities: "I'll do this for you, Allah, or Vishnu, and you'll do something or me." As we saw on Sept. 11, bargaining religions can cause big trouble sometimes: Fly an airplane into a building, and you get a big reward. Christianity, though, is about grace. We can't buy God off. We can't trade with him. Some folks never understand this, but those who do find it's enormously liberating.

Grace means that when a prodigal son returns, his past is not held against him. Some people keep close records of wrongs and hate the idea of brand-new beginnings, but Christmas celebrates liberation from the past. "He rules the world with truth and grace," the old carol tells us, and the beauty of Christian belief is that truth and grace go together in displaying the "wonders of His love. Let heaven and nature sing.

---Marvin Olasky is editor-in-chief of World, vice president for academic affairs of The King's College and a professor at The University of Texas. For additional commentary by Marvin Olasky go to www.worldmagblog.com.