There is an Islamic prophecy about a final apocalyptic war that says the “Romans”— which Islamists say are the Americans and Europeans of today—will land in Dabiq (a town in Syria) to avenge the “Roman” soldiers whom the Islamists have captured there.
The prophecy says after a ferocious battle in Dabiq, which will result in heavy casualties, Muslims will come together behind the jihadists at Dabiq and defeat the “Romans.” Turkey is then conquered by these Islamic forces. Shortly thereafter, the Islamic messiah (the Mahdi) and Jesus (who, after breaking a cross, becomes Islamic) will arrive on the scene.
That is the reason why the Islamic State beheaded American aid worker Peter Kassig in Dabiq. It is also why the Islamic State named its English-language magazine Dabiq.
The Islamic State wants its followers to know they are fulfilling prophecy and to entice potential recruits to participate in one of the most important moments in world history.
Warning — The following video contains extemely graphic footage of the execution by ISIS of American aid worker Peter Edward Kassig among others: