against heresy and ungodly ways of living. While this is surely no reason for entering into any compromise with doctrines which depart but a hair's breadth from Qorân and Sunnah, it necessitates methods of defence against heresy as unknown in Mohammed's time as heresy itself. "Necessity knows no law" is a principle fully accepted in Islâm; and heresy is an enemy of the faith that can only be defeated with dialectic weapons. So the religious truths preached by Mohammed have not been altered in any way; but under the stress of necessity they have been clad in modern armour, which has somewhat changed their aspect.
Moreover, Islâm has a theory, which alone is sufficient to justify the whole later development of doctrine as well as of law. This theory, whose importance for the system can hardly be overestimated, and which, nevertheless, has until very recent times constantly been overlooked by Western students of Islâm, finds its classical expression in the following words, put into the mouth of Mohammed: "My community will never agree in an error." In the terms more familiar to us, this means that the Mohammedan Church taken as a whole is infallible; that all the decisions on matters practical or theoretical, on which it is agreed, are binding upon its members. Nowhere else is the catholic instinct of Islâm more clearly expressed.
A faithful Mohammedan student, after having
