ijmāʿ, inIslamic law, the universal and infallible agreement of either the Muslimcommunity as a whole or Muslim scholars in particular. The consensus—sometimes justified through a saying from theHadith (traditions of the sayings and actions ofMuhammad), “My people will never agree in an error”—constitutes one of the sources of Islamic jurisprudence,uṣūl al-fiqh.

In Muslim history,ijmāʿ has always referred toconsensuses reached in the past, near or remote, and never tocontemporaneous agreement. It is thus a part of traditional authority.Ijmāʿ also has come to operate as a principle of toleration of different traditions withinIslam. It thus allows, for example, the four legal schools (madhhabs) equal authority and has probably validated many non-Muslim practices taken into Islam by converts.