The five days of worship had been planned for months, but ended up coinciding with the beginning of the offensive to take back Mosul – ISIS' last stronghold in Iraq – that began on October 17. Iraqi troops backed up by a US-led coalition began the battle to liberate the city which was overrun by ISIS militants in June 2014, and have since recaptured dozens of surrounding towns and villages.

"With the Iraqi's launching of efforts to liberate the 2.5 year captivated city of Mosul beginning just a couple days before we started our 100 hours, we couldn't help but feel it was the timing of the Lord to seek his face. This is exactly where he wanted us," Kelsie told Christian Today.

"What a powerful time having people who are persecuted believers, forced to leave their homes and all they own because they are followers of Jesus, get on their knees and pray for ISIS, their persecutors."

Over the five days, those gathered used several prayer focuses: unity in the global church, salvation for the lost, freedom for people in physical and spiritual captivity, and "for ISIS members to encounter the love of Jesus". Teams also went out to pray for the sick in local camps for the displaced, to play with children and share the gospel.

"As we closed out, even after 100 hours of continuous night and day worship the room was packed out," Kelsie said.

"You could hardly hear anyone talk because the shouting and dancing overtook everything else! Jesus was being glorified and hope released!! What a powerful five days it was, so hard to describe all that took place but that is a little glimpse."