Saeed Abedini has written a heartbreaking letter to supporters about his painful time in prison.

The pastor, currently imprisoned in Iran, will experience his first Christmas in prison entirely alone as all of his Iranian family have left the country.

In the letter released through the American Center for Law and Justice, Abedini described harsh conditions in the prison, with fellow prisoners being at times hostile and the prison guards making threats against him unless he he removed the small cross he had made out of paper and hung next to him as a sign of his faith.

While the days are very cold, he said that the glassless window beside his space in the cell makes sleeping "unbearable" most nights.

He also said some of his fellow prisoners did not like him because he is a convert and a pastor.  

"They look at me with shame as someone who has betrayed his former religion," wrote the one-time Muslim.  

He continued: "This is the first Christmas that I am completely without my family; all of my family is presently outside of the country. These conditions have made this upcoming Christmas season very hard, cold and shattering for me. It appears that I am alone with no one left beside me." 

Abedini is an Iranian with American citizenship and has been incarcerated in Iran since 2012, when he was arrested on charges of compromising national security.  

He was sentenced in January 2013 to eight years in prison for apparently undermining the Iranian government, although it is believed the real reason is because of his previous involvement in the house church movement.

According to his wife, Naghmeh, who resides in the US with their two children, Abedini is experiencing "severe pain" in prison as a result of beatings and would appreciate the prayers of supporters. 

"With the third Christmas approaching without Saeed, the journey is quite difficult. There are a lot of unknowns regarding Saeed's release and the timing, but both Saeed and I are trusting the Lord. Jesus Christ has never failed nor forsaken us," she said.

Abedini is also putting his faith in the Lord this Christmas.  In his letter, he concluded: "Christmas means that God came so that He would enter your hearts today and transform your lives and to replace your pain with indescribable joy...

"The same way that the heat from the earth's core melts the hard stones in itself and produces lava, the fiery love of God, Jesus Christ, through the virgin Mary's womb came to earth on Christmas to melt the hard heart of sin and wickedness of the world and removes them from our life."