He also authored a valuable book on jarḥ wa-taʿdīl (narrator criticism and accreditation). I have read it myself and excerpted a number of points that bear witness to his deep mastery of the discipline and the vastness of his memory.

ʿAbbās ibn Muḥammad al-Dūrī was once told about him and remarked, “In our view we ranked him alongside Aḥmad ibn Ḥanbal and Yaḥyā ibn Maʿīn.”

Among Aḥmad ibn ʿAbd Allah’s own pronouncements is his statement: “Whoever believes in the return of ʿAlī—may Allah be pleased with him—is a disbeliever, and whoever says that the Qurʾān is created is a disbeliever.”

It was also said that when the inquisition concerning the doctrine of the Qurʾān’s createdness began, he fled to the Maghrib, settled there, and his children were born in that land.

Some scholars observed, “Among us in the Maghrib, no one in his time equalled Abū al-Ḥasan Aḥmad ibn ʿAbd Allah in his knowledge of singular reports and his precision therein, nor in his asceticism and piety.” (1)

The historian-scholar Abū al-ʿArab Muḥammad ibn Aḥmad ibn Tamīm al-Qayrawānī related: “I asked the ḥāfiẓ Mālik ibn ʿĪsā al-ʿIfṣī (2): ‘Who is the most knowledgeable in hadith among those you have met?’ He replied, ‘Among the senior teachers, Aḥmad ibn ʿAbd Allah al-ʿIjlī.’”

Muḥammad ibn Aḥmad ibn Ghānim, the ḥāfiẓ, said: “I heard Aḥmad ibn Muʿtab (3)—a reliable Maghribī—say: ‘Yaḥyā ibn Maʿīn was asked about Aḥmad ibn ʿAbd Allah ibn Ṣāliḥ, and he replied, “He is trustworthy, the son of a trustworthy man.”’” (4)

Others maintained that Aḥmad ibn ʿAbd Allah settled in Ṭarābulus only in order to live in seclusion.