The worshippers close their eyes, bow heads, hold hands, and speak their hopes and prayers out loud.
"I praise God for reconciling between my father-in-law and his stepdaughters.... Prayer works!" rejoices one. "I pray for ... the sanctity of marriage," says another.
"I give thanks for not being hit in the explosion today, and for suicide bombers staying away," a third intones, the sound of a chopper almost drowning him out.
"Amen," they sing, a group of men and women in neat camouflage fatigues, pistols strapped on their legs and chests and Bibles open in their hands.
And then there is Ahmed. With his acid-wash jeans, white shirt, and ID badge reading "escort required," he stands among them – mumbling the prayers, tapping his shiny brown loafers as the guitarist strikes up a catchy hymn. He's included, and apart, at the same time.
A recent convert to Christianity, Ahmed, who asked that his real name not be used out of fear for his security, has begun to join the hour-long church services at the Kabul Afghanistan International Airport (KAIA) base most Thursday evenings.
Even without consorting with Westerners, Afghan Christians face consequences for practicing their faith.
Months ago, Ahmed's parents, having discovered he had become a Christian, threw him out of the house, tossing his clothes into the street behind him. Later, they forced him into marriage with a relative from Kunduz, hoping this might return him to the ways of Islam.
His young bride, he admits, has no idea of the truth. She thinks he is at work. He leaves home, walking down the potholed Kabul road, boarding one bus, then another – always looking over his shoulder.
Converting to Christianity, punishable by death under Taliban rule, is no longer a criminal offense, but remains a highly risky choice in this conservative Muslim country. Just two years ago, the new Constitution notwithstanding, an Afghan man was sentenced to death for converting – and was only reprieved, on grounds of insanity, after a massive international campaign. He later went into exile.
Christian groups estimate the number of Afghan Christians here ranges between 500 and 8,000 – in a country of over 30 million Muslims. Official churches don't exist, and congregants often gather in secret, using coded messages to direct them to the underground churches that move weekly. A few, like Ahmed, quietly join groups on coalition bases.
Christian expatriates can gather freely to pray or study in Afghanistan – but are not immune from the deep-seated animosity toward the religion either. The small number of Christian aid organizations with offices in the country keep a low profile and clearly state they are focused on humanitarian, and not religious work.
But last year, a group of 23 South Korean church volunteers were kidnapped in southern Afghanistan and two were killed before the others were released.
More recently, in October, Gayle Williams, a young woman working for Serve Afghanistan, a Britain-based Christian charity, was killed as she walked to work through a busy intersection in Kabul. The Taliban claimed responsibility, saying she was killed because she was proselytizing – a claim Serve Afghanistan has refuted, insisting the aid worker was running a project for disabled children.
Fear of being accused of proselytizing worries Capt. Scott Jensen, who leads the KAIA services, but he refuses to close the doors of his little wooden church to anyone.
"There are people turning to me saying the Islamic faith is not filling the hole within them. They want to explore Christianity," he says. "We don't do missionizing work, but we are defined by our love and we reach out in love."
Ahmed, who works on the base as a day laborer, was first introduced to Christianity a year ago, when a teacher at his English school in Kabul gave him an English-Dari Bible, he says.
He would stay up at night reading, and hide the book under his mattress when he went out. It was there that his mother found it, informing his father – who beat him before throwing him into the street.
Captain Jensen, an ordained Lutheran pastor from San Antonio who has logged 23 years in the military, is not in Afghanistan as an official chaplain, but rather as a communications director, in charge of keeping the KAIA network working, and training Afghan counterparts. He was to conduct his last service Thursday.
But, with no one else to hold regular non-Catholic services for the 2,200 troops on base, he volunteered to help. Jensen spends some 15 hours a week, he says, preparing services, writing a bulletin, and counseling those in need.
One day, he recounts, he got a phone call from someone who said he had some questions. "A man called and told me he had been reading the Bible in secret. He said, 'I want to talk to you about it.' "
That man was Ahmed, and it was the beginning of the journey that brought him here.
In time, a handful of other Afghans began contact with Jensen as well, all reaching out to him through trusted personal connections. All are welcome at services and care is taken to secretly ease their way onto the base, protect their identities, and make them feel at home.
"I don't get into the politics of it," says Sr. Master Sgt. Cedric Pinnock, an aircraft mechanic and regular at services. "I'm just glad we could provide them with community."
Back at the prayer circle, the hymn has ended and Jensen starts his benediction.
"Let us pray for those killed in the bombing today and give their families strength," he says, in reference to a suicide attack that left six dead downtown earlier that afternoon. "And let's pray for those who perpetuated this crime."
"Let us pray for the Christians in the underground church and for a day to come in which there is freedom of religion in Afghanistan – and each and every person can practice what they believe," he ends.
Bowed heads are lifted, and the congregants shake one anothers' hands. "May peace be with you," they say. "May peace be with you," Ahmed responds.