Imprisoned American pastor Saeed Abedini wrote to President Obama from his jail cell in Iran to thank him for standing up for persecuted Christians.
The President had a private meeting with Saeed's wife, Naghmeh and their children, Rebekka and Jacob, during a visit to Boise, Idaho last week, after she had petitioned to meet him.
Obama said at the meeting that freeing Saeed Abedini was a "top priority" for the Administration, and said he would try to get him home for his son's birthday in March.
In his letter Saeed thanked the President for the concern he had shown for him and his family.
He said his wife and children "have had a heavy burden to carry in my absence, and your presence helped to relieve some of that burden."
He continued: "Thank you for your fatherly compassion of letting Jacob know that you will try to get me home by his birthday. I know that as a father you can truly understand the pain and anguish of my children living without their father and the burden that is on my wife as a single mother.
"I also know how encouraged Christians around the world were to also hear of this meeting. Nothing is more valuable to the body of Christ than to see how the Lord is in control and moves ahead of countries and leadership through united prayer."
Saeed thanked the President for standing up for persecuted Christians around the world.
"Thank you again for standing up for my family and I and for thousands of Christians across the world who are persecuted for their faith in Jesus Christ. President Obama, you have my prayers from inside of these walls. I pray for God's guidance, wisdom and blessing for you as you lead this great nation," he wrote.
Naghmeh told The Blaze last week that her 10-minute meeting with the President was "emotional" and that she felt there was a real "heart connection" as he heard her husband's story.
"I could see in his eyes that he's a dad and for him to see that that's what Jacob wants – it was a really emotional moment," Naghmeh said. She had fasted and prayed for three days prior to Obama's visit to her hometown, in the hope that he would meet with her.
Pastor Saeed is currently serving an eight-year prison sentence in Iran for "threatening the security of the state".
Naghmeh has repeatedly challenged the US government to speak up for her husband, and has criticised the administration's failure to respond with the urgency called for by campaigners. "I thought I would have to fight the Iranian government. I never anticipated that I would have to battle my own government," she said during a 2013 congressional hearing in Washington.
The American Center for Law and Justice (ACLJ), which represents Saeed, said: "We agree with Pastor Saeed that President Obama's willingness to meet with his family sends a powerful message about America's priorities and resolve to defend persecuted Christians."
The ACLJ called on Christians to urge President Obama to "take action on his word" and sign the petition for his release at BeHeardProject.com.