Nowhere specifically, of course. If you want ObL’s justification, you can peruse the lengthy Ladenese Epistle. In it you’ll see a very thorough intertwining of political arguments with appeals to religious authority, particularly the rather regressive medieval theologian Ibn Taymiyyah, godfather of the modern Wahhabi and Deobandi movements, plus many references to hadith. Qur’anic passages are used more sparingly, in passing and arguably out of context.
This mostly proves ObL’s theology is kinda crappy. But just like the Crusading theology developed by the medieval church was a rather torturous philosophical affair, so to the justifications of the salafist-jihadists, who find creative loopholes to try to justify normally un-Islamic concepts like suicide and harming non-combatants. But both examples should still rightly be regarded as religious in motivation, however shitty the reasoning. ObL was enraged in part because non-Muslim troops were seen to be “defiling” the soil on which are situated the holy cities of Mecca and Medina - that’s idiocy, but it’s religious idiocy.
No, but Islam is still the motivator for this particular group of killers. Or more accurately, certain aspects of their version of Islam are completely emeshed into their motivations, providing both reason and justification in their minds.
No, sorry - it was fundamental.
I think we’re talking past each other a bit. The OP said:
To which I should have perhaps more clearly replied:
1.) Yes, all religions have kooks and yes it is wrong to judge a religion by its fanatics. and…
2.) But yes, some aspect of Islamic faith/politics were imperative to the attacks. They were imperative because it was the internal religious foment and the associated political dispute with its ruling house in Saudi Arabia that was by far the biggest motivator for ObL. His faith, a particularly violent and purist take on Wahhabi Sunnism, is what propelled his actions.
That this was the case should not be taken as an indictment of Islam as a whole, anymore than the insanity of Reverend Phelps should be taken as an indictment of Christianity as a whole.