In the past few weeks, I have been asked regularly what we learned from September 11. The greatest lesson concerned religion. And the lessons are as much about Us as about Them. After 9/11, many commentators focused intensely on Islam, trying to determine what features of that faith led its adherents to bloodshed. Many writers have presented Islam as a stark contrast to Christianity and Judaism, and portrayed a struggle of darkness against light. The Qur’an, in this view, is something like a terrorist manifesto, with so many verses about battles, swords and blood. What’s so startling about this approach is what it says about how little Christians and Jews seem to know about their own scriptures, and their own history.