ISIS’ Harsh Brand of Islam Is Rooted in Austere Saudi Creed -

"This approach is at odds with the more mainstream Islamist and jihadist thinking that forms the genealogy of Al Qaeda, and it has led to a fundamentally different view of violence. Al Qaeda grew out of a radical tradition that viewed Muslim states and societies as having fallen into sinful unbelief, and embraced violence as a tool to redeem them. But the Wahhabi tradition embraced the killing of those deemed unbelievers as essential to purifying the community of the faithful."