In the Islamic world, from the beginning, Islam was the primary basis of both identity and loyalty. We think of a nation subdivided into religions. They think, rather, of a religion subdivided into nations. It is the ultimate definition, the prime definition and the one that determines, as I said, not only identity, but also basic loyalty. And this is quite independent of religious belief. In Islam, there isn't or rather, there wasn't until recently any such thing as the church, in the Christian sense of that word. The mosque is a place of worship. It's a building, a place of worship and study. And in that sense, it is the equivalent of the church. But in the sense of an institution with a hierarchy and its own laws and usages, there was no such thing in Islam until very recently. And one of the achievements of the Islamic Revolution in Iran has been to endow an Islamic country for the first time with the equivalents of a pope, a college of cardinals, a bench of bishops and, above all, an inquisition. All these were previously unknown and nonexistent in the Islamic world.
Bernard Lewis