The event has been organised by Life Agape and the Chaldean Catholic Church and will be broadcast by the Christian Satellite network SAT-7.
Iraq
Population: 35.8 million
Christian population: Approx. 500,000
Christians have been living in Iraq for almost 2000 years.
Recent war, Islamic extremism and economic uncertainty has seen the number of Christians dramatically decrease as they face persecution or become displaced.
The meeting is taking place in Erbil. Among those in attendance will be thousands of Christians who have been displaced by ISIS.
Some of those who escaped ISIS will share their testimonies, including representatives from villages and towns near Mosul.
Attendees are expected to pray for the ongoing Mosul offensive to liberate the towns occupied by ISIS.
SAT-7 Arabic Programming Director George Makeen said the event climax will see thousands of Iraqi believers coming together to stand together in the shape of a cross, adding, "Then they will send up prayers for Iraq on balloons as a symbol of raising prayer on behalf of the whole nation."
The event marks the end of a nationwide prayer network fast organised by Life Agape within Iraq.
Referring to the invasion of Mosul and the Nineveh Plain by IS in 2014, Life Agape Iraq Director Maher Barbary said, "More than two years ago the Church had a vicious attack that left it in despair. They saw the broken buildings of the Church and the Christian families displaced inside and outside Iraq."
"But," he continued, "we and others believe God has a different plan, a plan that can turn this dark picture into a bright picture".