They are risking their own lives to capture Muslim souls one at a time.
In southern Russia, on the Eastern shore of the Caspian Sea, sits Dagestan, the most dangerous province in the country. Muslims fight Russian forces almost daily to take over the province for Islam.
Yet, away from the front lines, a small band of Christians secretly shares the gospel among Muslims.
One thousand miles from Moscow, Russian forces are in a 20-year fight against an Islamic rebellion. There are murders, assassinations, and bombings in the province virtually every day.
Ultraconservative Muslims want Islam to rule this corner of the country known as the Northern Caucasus. Dagestan is heart of the insurgency.
In 1999, a group of radical Muslims attempted to turn Dagestan into an emirate ruled by Islamic Sharia law. The Russian army stepped in and quickly stamped that out.
But since then, this province, which is home to about 2.5 million people, has some 3,000 mosques and counting.
There's a segment of the society, especially among youth, that's become more radicalized. They want to follow a pure form of Islam.
According to polls one in three Dagestanis back stoning of adulterers and chopping off thieves hands.
On a recent afternoon, CBN News met up with "Roman," a pastor of an underground church. They meet in small, discreet home groups, because many of those who attend are converts from Islam.
CBN News agreed to conceal their identities for protection.
"How open are the Muslims in Dagestan to hearing about Jesus Christ?" CBN News asked.
"I have to say that there are some who are open and have heard about Christ but we have to be very careful," Roman said.
"How dangerous is it to be a Christian today in Dagestan?" CBN News asked.
"For some believers it could mean death. For others it means enduring daily persecution or harassment," Roman said.
On July 15, 2010, a gunman killed Roman's close friend Artur Suleimanov. Forty-nine-year-old Suleimanov led the biggest protestant congregation in Dagestan. Local media had accused him of actively converting Muslims.
"I wondered if I was next on the list. To be honest, I wanted to leave the city immediately and not come back," Roman said.
But three years after his friend's death, Roman said he's more determined than ever to share the love of Christ.
"I get routine threats from Muslims. This is life," he said.
Dagestan is more than 90 percent Muslim. No one knows for sure how many secret evangelical Christians there are. Believers say the church in Dagestan is focused in two areas: discipleship and church planting.
Fifty people attend Roman's congregation. Tweny-two of them are full-time church planters.
"Sometimes my wife jokes that we won't have a church left since everyone's being sent out," he said. "I don't want to build a church and fill it up with people. Once someone has accepted the Lord, we disciple then send them out."
Valentine, one of the church planters, serves in a remote village close to the Chechen border.
"Over the last six or seven years the villages have become breeding grounds for radical Muslims. Young people are recruited from here and join the militant ranks. We try to reach them before that happens," Valentine said.
Another believer was severely beaten when he tried sharing the gospel with a Muslim girl.
"Nothing is going to stop the work of the Holy Spirit here. Just as God loves the Chinese, Americans, Germans, he has great love for Dagestan, Chechnya, and the whole Caucasus," one secret believer said.
In the Shadows
Oksana, another secret believer, teaches at a Muslim school. She can't openly talk about Christianity, but when students ask about her faith, she has an answer.
"When I came to the school I was told by the students that they hated Christians. But their hearts have changed," she said. "The only thing I can do is live out my Christian life in humility and love and leave the rest to God."
Dagestan and the Northern Caucasus is one of the least-evangelized places on earth. The rising Islamic fervor has prevented many Russians from even visiting the area.
But for Roman, Valentine, and other believers who work quietly in the shadows, it's a risk worth taking to make the name of Christ known.
"We minister to drug addicts, we have an outreach to young people, and we are training the next generation of church leaders. This is our strategy," Roman said. "We may not see the fruits of all our labor immediately, but we are called to lay the foundation, to till the soil, for future generations."