Pastor Su Tianfu, a Protestant preacher from Guiyang, China, reads the Bible on his iPhone. His church was recently shuttered in a sweeping government crackdown. (Emily Rauhala/The Post)

Pastor Su Tianfu slides into the back seat and tells the driver to hit it.

He looks over his shoulder: “Is there anybody following us?”

It is days before Christmas, but instead of working on his sermon, Su is giving his tail the slip.

The slight and soft-spoken Protestant preacher is no stranger to surveillance. Su has worked for years in China’s unregistered “house churches,” and he said he has been interrogated more times than he can count.

But even Su is surprised by what has happened in Guiyang this month: a crackdown that has led to the shuttering of the thriving Living Stone Church, the detention of a pastor on charges of “possessing state secrets” and the shadowing of dozens of churchgoers by police.

Chinese Christians driving in the city of Guiyang, in China's southwestern Guizhou province. (Emily Rauhala/The Post)

A local government directive leaked to China Aid, a Texas-based Christian group, and reviewed by The Washington Post advises local Communist Party cadres that shutting down the church is necessary to “maintain social stability”— a catchall phrase often used to justify sweeping clampdowns.

The Dec. 9 raid on the church in a relatively sleepy provincial capital is conspicuous because of the timing — about two weeks before Christmas — and because the government’s tactics were revealed.

But it also speaks to a broader pattern of religious repression that is playing out beyond China’s mountainous southwest, as the officially atheist Communist Party struggles to control the spread of religion amid a broader push to thwart dissent.

“The overall environment in the past few years has been harsh,” said Yang Fenggang, director of Purdue University’s Center on Religion and Chinese Society. “There’s a tightened control over civil society in general, including churches.”

A question of faith

Unlike in many parts of the West, Christianity is thriving in China.

Because of tight restrictions on religious practices, reliable figures are hard to find, but the Chinese government generally puts the number of Protestants (a group it calls “Christians”) at 23 million and the number of Catholics at more than 5 million.

Foreign scholars estimate that there are 67 million to 100 million Christians in China — compared with 87 million Communist Party cadres. Yang estimates that China will be home to 250 million Christians by 2030. Evangelical Protestants, like Su, are the fastest-growing group.

The Communist Party has a complicated, often contradictory, view of faith: The constitution protects the right to religion, but the state is unwilling to relinquish control.

“The Chinese Communist Party is violently allergic to non-party organizing vehicles, whether they’re nonprofits, libraries or churches,” said Sophie Richardson, China director at Human Rights Watch.

That means you can be a Christian, a Tibetan Buddhist or a Muslim, but only on the government’s terms. Christians must limit themselves to “normal religious activity” at a state-backed church, where party dogma trumps religious doctrine and where proselytizing is forbidden. Local officials decide what “normal” means — and what is legal.

That level of discretion gives authorities wide berth to close churches, tear down crosses or arrest Christian campaigners as they see fit — a sore point between the United States and China.

This summer, Chinese authorities arrested Zhang Kai, a lawyer fighting the removal of crosses in Zhejiang province, just days before the arrival of the U.S. envoy for international religious freedom, David Saperstein, and weeks before President Xi Jinping’s state visit to the United States.

It put pressure on President Obama to raise the issue in meetings with the Chinese leader. In a news conference with Xi, Obama said he had expressed, in “candid terms,” his concerns about church closures in the country.

China rejects such criticism as interference. In October, state-backed religious groups urged the United States to stop acting like an “international religious police force,” according to the People’s Daily, the official newspaper of China’s Communist Party.

“Religious personnel embrace the rule of the Communist Party of China,” it said, while “a very small number of people . . . engaged in criminal activities under the banner of religious freedom have been punished according to law.”

And for the past year, members of the Living Stone Church have felt the full force of the law — and the vast security apparatus that accompanies it.

In a legal gray zone

Christianity has a long history here. Foreign missionaries have been working in rural Guizhou province, of which Guiyang is the capital, since the 1800s, spreading the faith among ethnic minorities in villages that dot the region’s thimble-shaped peaks. The pogroms of the Cultural Revolution led to the destruction of most churches and the persecution of many Christians, but the faith survived here quietly.

China’s economic expansion has since brought many of the villagers to towns and cities, where a sense of social dislocation and a longing for community are fueling a religious awakening.

When Living Stone was founded in 2009, it had about 30 members. By the time the church closed, services drew several hundred people at a time, according to interviews with seven members.

Here, as elsewhere, unregistered “house churches” operate in a gray zone — they are thriving but illegal, always at risk and sometimes ignored. As such, it is hard to know why and when crackdowns will occur.

A turning point for Living Stone seems to have been the acquisition of a meeting place. Church members pooled their money and last year took possession of a 7,000-square-foot space on the 24th floor of an office building called the Guiyang International Center.

Authorities let them meet there, sometimes, urging them to keep the gatherings small and social, not religious. After more than a year of warnings, arrests and threats, church members were given an ultimatum: Join a state-backed church or get shut down.

On Dec. 9, officials and security personnel swarmed the property, taking Bibles and songbooks.

A colleague of Su’s, Pastor Yang Hua, was detained when he tried to block police from taking security footage and computer equipment, two witnesses said. The day he was to be released, he was detained again, this time on charges of “possessing state secrets.”

Now, at the Guiyang International Center, the elevator no longer stops at the 24th floor, and police guard the entrance to the church.

“This is the site of an illegal cult and has been banned,” one officer yelled. “We are here to stop people from joining.”

They may succeed — for now.

Local officials say Living Stone’s members can join a state-backed church, and some probably will.

But many of Living Stone’s faithful would sooner relinquish Christianity altogether than join a government church.

“When it comes to our faith, we do not want to submit ourselves to a political organization. Our only leader is God in heaven,” said Zhang Tan, a church member who used to work for the local government.

Su said he would continue to worship on his own terms, even if it meant holding this year’s Christmas service at home.

“Faith and love of God cannot be chained,” he said.

Xu Yangjingjing contributed to this report.