Some people hold that Hadith-ul-Ahad (a Hadith which at some point in the chain has only a single narrator) cannot be used as evidence in issues related to ‘Aqidah (creed),
as they include supposition and ‘Aqidah cannot be established on supposition. They attribute this opinion to two of the Four Imams (Imams Abu Hanifah, Malik, Al-Shafi‘y, and Ahmad). What is your comment on this subject?
The Hadith-ul-Ahad that are Sahih (a Hadith that has been transmitted by people known for their uprightness and exactitude; free from eccentricity and blemish) can be used with certitude if they are supported by other evidence, otherwise they will indicate probability. In either case, this type of Hadith must be referred to in establishing creedal issues and all other Islamic legal rulings. There is a lot of evidence to support this view, as that stated by
Abu Muhammad ‘Aly ibn Hazm in a research study on the Sunnah, in the book entitled, "Al-Ihkam fy Usul Al-Ahkam (Perfection of the Fundamentals of Judgments)" and by
Abu ‘Abdullah Ibn Qayyim Al-Jawziyyah in: "Al-Sawa‘iq Al-Mursalah ‘ala Al-Jahmiyyah wa Al-Mu‘attilah". Among the evidence cited is the fact that the Prophet (peace be upon him) sent individual delegates with his letters to rulers such as
Caesar, to invite them to Islam, to both its ‘Aqidah (creed) and Shar‘iah (law). (Part No. 4; Page No. 365) Had those delegates not been sufficient to establish evidence, for being individuals, the Messenger (peace be upon him) would not have sent his letters with just one of them, instead he would have sent them with a number of delegates to reach the level of Tawatur (being widely transmitted by a significant number of narrators whose agreement upon a lie is impossible). This would have established the evidence required by those who claim that Hadith-ul-Ahad must not be taken as proof in creedal issues. Among the delegates that the Prophet (peace be upon him) sent was
Mu‘adh, whom the Prophet (peace be upon him) also sent to
Yemen as the governor and as a Da‘y (caller) to Islam, to both its ‘Aqidah and Shar‘iah. So, the evidence for this is derived from the letters that were sent with individuals and other examples taken from similar actions of the Prophet (peace be upon him). If you would like to further investigate and study the evidence, you can refer to the above-mentioned two books for more information.With regard to attributing the above claim to two of the Four Imams, this has no basis. The views of the Four Imams concerning the use of Hadith-ul-Ahad as evidence are well-known and attested to.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.