Father Charbel Issu stands before a shattered altar, spreads out his hands and begins leading a group of Kalashnikov-wielding militia fighters in prayer.
"Our father who art in heaven," they chant.
"Hallowed be thy name."
On the wall in front of them, graffiti scrawled in black spray paint reads "Allahu Akbar (God is the greatest)".
Iraqi fighters battling to oust the Islamic State group from Mosul recaptured the Catholic Mar Behnam monastery on Sunday, allowing its priests to return.
Dating back to the fourth century AD, the Syriac Catholic monastery lies just 30 kilometres (20 miles) south of Iraq's second city which became a bastion of the jihadist group after it swept across northern Iraq in 2014.
When they seized it in 2014, the jihadists sacked the monastery, smashing carvings off the wall, decapitating a statue of the Virgin Mary and leaving the building as an empty shell.
The priests fled and most have not returned.
"I am both happy and sad," Issu, a former director of the monastery, told AFP on his first visit back.
"I'm happy to return to these holy places, to see this monastery where I spent a year and a half as superior.
"At the same time, I'm sad to see it like this, in such bad condition, demolished. It hurts my heart," he said.
In front of the main building, he peered down on the rubble covering the tombs of Mar Behnam -- a Syriac saint from whom the monastery gets its name -- and his sister Sara.
In 2015, IS jihadists posted a video of themselves blowing up the tomb. Today, little remains.
It was part of an IS campaign of destruction as it swept across the region.
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The jihadists trashed other faiths' places of worship and blew up ancient sites such as the Assyrian city of Nimrud and the Greco-Roman remains of Palmyra in neighbouring Syria.
- Babylon Brigade -
As it seized their areas, IS gave Christians three options: leave, pay a special tax or convert to Islam. Most decided to flee.
Now, rebuilding the community will be tough, Issu said.
"You should see their houses," he said. "Fifty percent of their houses have been torched."
The attacks are the latest in a string of abuses against Iraq's Christian minority in recent years. Issu said reining in tensions between religions is a daunting task.
"It will be very difficult," he said. "But we hope and hope."
As he toured the monastery, the small, grey-haired priest was escorted by heavily armed fighters from a Christian militia, who wore crosses and bullet belts over their camouflage.
They are part of the Babylon Brigade, a militia formed by Christians across Iraq to battle IS after it swept through the country.
They were part of the contingent that took back the area around the monastery.
The Brigade fights under the banner of the Popular Mobilisation forces, an umbrella for 40 mainly Shiite militias formed in a bid to counter the jihadists.
They helped in the operation to wrest the monastery from the jihadists. They say they want to go on fighting until they have pushed IS out of all the Christian sites it holds in Iraq -- and even in Syria.
"We are very sad to see all the destruction here but the happiness of the victory has overwhelmed us and we are so joyful to be standing here," said Colonel Dhafer Luis.
"I hope that the Christians return to this area and I call on them to return," he said.
"We have shown by our example that even though we are a small group we captured this place -- what you need is a faithful heart."