INTRODUCTION

The Imāmīs provide the richest and most continuous documentation of the doctrine of forbidding wrong of any sect or school. Though early Imāmī literature is less abundant than that of Sunnī tradition or the ḥanbalite law-school in the same period, it is far more plentiful than the fragmentary Mu'tazilite and Zaydī record. Thereafter we have at our disposal a succession of Imāmī discussions of the duty which is more or less unbroken from the fifth/eleventh century till the present day. We owe this wealth of material to three circumstances. First, the Imāmīs, like the Zaydīs, made it a practice to give a place to forbidding wrong in their law-books. Secondly, and unlike the Zaydīs, the Imāmīs waxed numerous over the centuries, and generated a literary heritage that was commensurately large. Thirdly, recent developments in Iran have helped to make this heritage increasingly available in print. We can accordingly set out to write a more sustained narrative of the history of the doctrine in Imāmism than is possible for any other sect or school. But against the continuity of the record must be set its narrowness of focus. What the Imāmī scholars have to offer is repeated coverage of doctrinal issues of a kind familiar from the Mu'tazilite tradition. It is in the nature of this material that it displays only a limited number of points of contact with the outside world.