Consensus (ijmāʿ)
Definition:
Linguistically, ijmāʿ denotes firm resolve and agreement.
Technically, it is the unanimous agreement of the mujtahids (qualified jurist-scholars) of this Ummah, after the Prophet ﷺ, on a point of Sacred Law.

• By our saying “unanimous agreement,” we exclude any dissent, even from a single scholar; if disagreement exists, consensus is not formed.

• By our saying “mujtahids,” we exclude laypeople and followers of taqlīd; neither their accord nor their dissent is consequential.

• By our saying “of this Ummah,” we exclude the consensus of other communities; such agreement carries no weight here.

• By our saying “after the Prophet ﷺ,” we exclude the Companions’ agreements reached during his lifetime. These are not considered ijmāʿ as legal evidence, because the proof in that case derives directly from the Sunnah—his words, deeds, or tacit approvals. Hence, when a Companion reports, “We used to do such-and-such during the Prophet’s time,” the report is treated as marfūʿ ḥukman (effectively traced back to the Prophet himself), not as a transmission of ijmāʿ.

• By our saying “on a point of Sacred Law,” we exclude their agreement on purely rational or customary matters; such issues are outside the scope of our discussion, for ijmāʿ is examined only as a source of legal evidence.

Ijmāʿ constitutes binding proof on the strength of several evidences, among them: