U.S. veteran Brett Felton told CBS’ 60 Minutes that he returned to Iraq to fight against the Islamic State (ISIS/ISIL) to defend the Christians the terrorist group is liquidating as it expands its Caliphate through the Middle East.

“People say, ‘You’re crazy for doin’ this,'” explained Felton. “I think people are crazy for not doing their part, to be honest with you.”

Felton went to Iraq in 2006 with the 10th Mountain Division, 2nd Battalion, 14th Infantry Regiment. He was discharged in 2007, but wanted to return as soon as he returned to America. He made his way back through Lebanon as a “soldier of Christ.” Jeff Newton, a producer of 60 Minutes, interviewed Felton in Iraq.

“If you look at him, he’s literally all tattooed out like a biker,” described Newton. “But if you look really closely at his tattoos, they’re like Jesus Christ crying blood tears out of his eyes and stuff like that–so he’s kind of a hardcore Christian.”

The crew discovered Felton in a village just north of Mosul. The Islamic State captured Mosul, Iraq’s second largest city, in June 2014. For over 2,000 years, Mosul was home to one of the largest Christian communities in the world and lived peacefully among the Muslims. But when the Islamic State came barreling in, the militants told Christians to convert, pay a protection tax (jizya), or leave. If people refused, the militants murdered them.

A few did stay behind to fight for their homes. Correspondent Lara Logan said only some are professional soldiers.

“They’re under-funded. They don’t have good weapons. They’re completely outgunned by the Islamic State,” she said. “When you’re with them, you have this terrible feeling that many of them would be massacred if the Islamic State really turned its attention to taking back those those [sic] villages.”

The Monastery of St. Matthew, one of the oldest in the world, is on a mountain that overlooks “the Nineveh Plains of ancient Mesopotamia.” Monks still pray the same prayers from the fourth century, but only seven remain.

Father Joseph Ibrahim spoke to Logan.

Lara Logan: You do the service in Aramaic?

Father Joseph Ibrahim: Yes.

Lara Logan: Which was the language of Jesus.

Father Joseph Ibrahim: Yes.

Lara Logan: Are you among the last people on earth to speak this language?

Father Joseph Ibrahim: We think so because we kept this language through the language of prayers.

The monastery was founded in 363. It survived “the Persian and Ottoman empires, Mongol invaders, and Kurdish conquests.” But now the Islamic State threatens the monastery.

People like Felton are going to make sure Christian history is preserved. “To me, for the Christians here, it would be an honor to give my life helping these people,” said Felton.