Proofs for the mandatory acceptance of solitary reports (ḥadīth al-āḥād) in matters of belief:

There are additional proofs—more precise in their indication than the ones already cited—showing that a single-transmitter report must be accepted in creed. I deem it necessary to set out some of them and explain the relevance of each.

First proof: the Almighty says, “The believers should not all go out at once. Rather, from every group among them, a party should set out so that they may gain a sound understanding of the religion and warn their people when they return to them—perhaps they will take heed” (Qur’an 9:122).

In this verse Allah urges the believers that a party of them travel to the Prophet (peace and blessings be upon him) to learn their religion directly from him and acquire deep understanding of it.

There is no doubt that this exhortation is not confined to what jurists call subsidiary issues and practical rulings; rather, it is broader than that. Indeed, it is certain that an instructor begins with what is most important and then proceeds to what is next, and it is beyond dispute that matters of belief are weightier than matters of practice.

For that very reason some have asserted that doctrines cannot be established by solitary reports. Yet this noble verse refutes their claim: just as Allah commands that party to learn and understand both creed and rulings, He likewise commands them—upon their return—to warn their people with whatever they have learned of creed as well as rulings.