An Iranian Christian is questioning the crime he has been imprisoned for from his jail cell.

In a poignant and honest letter, Naser Navard Goltapeh openly asked why worship in a home church is considered an "action against national security" in Iran.

Goltapeh was sentenced to a 10-year term of imprisonment in Evin prison in January 2018. Two years after his initial detainment, Goltapeh is questioning why, reports Barnabas Aid.

"Today marks more than two years since I have been detained in prison for the fabricated charge of acting against national security by running house churches, even though religious ceremonies are part of our religion," the prisoner wrote.

In his letter, he mentions Christians are recognized in Iran as a religious minority, and, according to the country's constitution, are "free to practise their religion."

"I do not know by what logic or under which crime this heavy sentence has been imposed upon me. I hope that Christ’s love will spread through the voice of imprisoned Christians throughout the world," Goltapeh says.

Goltapeh's imprisonment came after he was arrested in July 2017. The police conducted a secret raid on a church meeting and Goltapeh was arrested along with three Azerbaijani Christians.

The Iranian Christian was convicted of the crime of taking part in an "illegal gathering" which "threatens the security of Iran."

Health concerns prompted Goltapeh's family to raise alarm in April 2018. Goltapeh had been kept in solitary confinement and interrogated for two months and was suffering from a severe gum infection that required treatment or he would lose his teeth.

Goltapeh is a Farsi-speaking man who converted to Christianity from Islam. Christian worship meetings in Farsi, Barnabas Aid reports, are targeted by Iranian authorities in an attempt to prevent conversions like Goltapeh's.