The Syrian town of Dabiq is where the Prophet Mohammed is supposed to have predicted that the armies of Islam and "Rome" would meet for the final battle that will precede the end of time and the triumph of true Islam.
When American aid worker Peter Kassig was murdered by ISIS in November, "Jihadi John" -- the masked British murderer who has appeared in so many ISIS videos -- said of Kassig: "We bury the first crusader in Dabiq, eagerly waiting for the rest of your armies to arrive."
In other words, ISIS wants a Western ground force to invade Syria, as that will confirm the prophecy about Dabiq.
We live in an increasingly secularized world, so it's sometimes difficult to take seriously the deeply held religious beliefs of others. For many of us the idea that the end of times will come with a battle between "Rome" and Islam at the obscure Syrian town of Dabiq is as absurd as the belief that the Mayans had that their human sacrifices could influence future events.
But for ISIS, the Dabiq prophecy is deadly serious. Members of ISIS believe that they are the vanguard fighting a religious war, which Allah has determined will be won by the forces of true Islam.
Basically, they're trying to hasten their religion's prophesied end-of-the-world.