Radical movements reflect the civilization that spawned them

“Osama bin Laden and his Al Qaeda followers may not represent Islam, and their statements and their actions directly contradict basic Islamic principles and teachings, but they do arise from within Muslim civilization, just as Hitler and the Nazis arose from within Christian civilization, so they must be seen in their own cultural, religious, and historical context. If one looks at the historical record, the Muslim approach to war does not differ greatly from that of Christians, or that of Jews in the very ancient and very modern periods when the option was open to them. While Muslims, perhaps more frequently than Christians, made war against the followers of other faiths to bring them within the scope of Islam, Christians — with the notable exception of the Crusades, which were themselves an imitation of Muslim practice — were more prone to fight internal religious wars against those whom they saw as schismatics or heretics. Islam, no doubt owing to the political and military involvement of its founder, takes what one might call a more pragmatic view than the Gospels of the realities of societal relationships. Because war for the faith has been a religious obligation within Islam from the beginning, it is elaborately regulated. Islamic religious law, or the Sharia, deals in some detail with such matters as the opening, conclusion, and resumption of hostilities, the avoidance of injury to noncombatants, the treatment of prisoners, the division of booty, and even the types of weapons that may be used. Some of these rules have been explained away by modern radical commentators who support the fundamentalists; others are simply disregarded.”
–Bernard Lewis, “The Revolt of Islam”, The New Yorker, November 19, 2001