Incorrect answer, Sidney.

They emulate “The Prophet”, and hope to gain money, arms, prestige in society, and probably the rule of Saudi Arabia, all “worldy things”. In this way they please the Prophet Mohammed, their intercessor for Allah. Allah himself is unknowable and unreachable, by their beliefs. They only mouth that nonsense about “72 virgins” for the crowd of confused Muslims that is undecided and to befuddle the Western media with their alleged fearlessness and willingness to die. The powerful among the Muslims are always willing to have the lesser men die on their behalf, of course.

Osama bin Ladin has stated all along that his first priority was to “raise the Umma”, meaning the body of believing Muslims, to the state of Jihad. Significant members of the House of Saud have had the temerity to work with the Crusaders (that’s the US, among others), and are thus ripe for war and execution by True Believers, per their own Koran.