- Alan Henning's colleagues thought his abduction was a temporary measure
- Barbara Henning says she has been trying to communicate with ISIS
- She says ISIS has not responded to the messages
- "I cannot see how it could assist" any ISIS cause to kill her husband, she says
The wife of British hostage Alan Henning pleaded Saturday with the Islamic State terror group to release her husband, describing him as a "peaceful, selfless man" who was only in Syria to help people in need.
"I cannot see how it could assist any State's cause to allow the world to see a man like Alan dying," according to a message from Barbara Henning released by the UK Foreign Office.
"I have been trying to communicate with the Islamic State and the people holding Alan. I have sent some really important messages but they have not been responded to."
In a videotaped execution of aid worker David Haines, made public last week, ISIS threatened to kill Henning next if the United States continued its airstrikes targeting the group's fighters in Iraq.
Henning, a taxi driver from Bolton in northern England, was part of a team of volunteers traveling to Syria to deliver food and water to people in need when he was abducted in December 2013.
"Alan is a peaceful, selfless man who left his family and his job as a taxi driver in the UK to drive in a convoy all the way to Syria with his Muslim colleagues and friends to help those most in need," Henning's wife said in the statement.
"When he was taken he was driving an ambulance full of food and water to be handed out to anyone in need."
She said his actions were an act of compassion.
"I pray that the people holding Alan respond to my messages and contact me before it is too late.
"When they hear this message I implore the people of the Islamic State to see it in their hearts to release my husband Alan Henning."
The plea comes weeks after the mother of American freelance journalist James Foley called on ISIS to release her son. Days after that plea, ISIS released a video of Foley's beheading.
American journalist Steven Sotloff also was executed by ISIS.
Henning, a father of two, was making his fourth trip to Syria with an aid convoy when he was abducted.
While part of the convoy stopped at the Turkish border, Henning -- the only non-Muslim in the group -- volunteered to cross into Syria with a 10-person advance party.
In video shot on that day, he explained part of his rationale for answering the call to help. "It's all worthwhile when you see what is needed actually gets where it needs to go," he said, before hugging a colleague.
Henning was kidnapped by ISIS a day after the video was made.
Dr. Shameela Islam-Zulfiqar, a volunteer doctor who stayed behind the main part of the convoy at the Turkish border, said they got a phone call saying Henning had been taken by masked gunmen.
"We thought it was just a temporary measure, him being a non-Muslim and being visibly English," she said. "We thought they'd question him and let him go."