This allegation goes back only to Zāhir ibn Aḥmad, as stated in his biography in Shadharāt 3/131. Most probably it is a mistake born of haste: he wished to attribute the report to al-Ashʿarī, but when his eye fell on a narration about him, he assigned it to him instead.

This same Zāhir was one of the Shāfiʿī authorities; he died in 389 AH at the age of ninety-six.

293 – The ḥāfiẓ, the proof, Abū al-Qāsim Ibn ʿAsākir said in his book Tab’yīn Kadhib al-Muftarī fīmā nusiba ilā al-Ashʿarī:

“If Abū al-Hasan—may Allah have mercy on him—was, as has been related, sound in creed and his school deemed correct by those of learning and critical insight; if the foremost worshippers agree with him in most of what he upholds, and none but the ignorant and obstinate find fault with his doctrine, then his creed must be conveyed faithfully and accurately so that people may know the true state of his religious belief. Listen, therefore, to what he recorded in al-Ibānah, for he said:

‘Praise belongs to Allah, the One, the Mighty, the Glorious; unrivalled in His oneness, exalted in His majesty, beyond the reach of the attributes of slaves, without peer or equal…’

In the opening of his treatise he refuted the Muʿtazilah, the Qadariyyah, the Jahmiyyah, and the Rāfiḍah. He went on to say:

‘If someone were to ask, “You have rejected the doctrine of the Muʿtazilah, the Qadariyyah, the Jahmiyyah¹, the Ḥarūriyyah, the Rāfiḍah, and the Murjiʾah—so tell us what you yourselves believe, and the religion to which you adhere.” We would answer:

“Our statement, which we profess, and our religion, by which we worship, is to hold fast to the Book of Allah and the sunnah of His Prophet ﷺ, and to what has been transmitted from the Companions, the Successors, and the leading scholars of ḥadith; to all of that we cling. We also affirm what Aḥmad ibn Ḥanbal—may Allah illumine his face—held, and we keep aloof from whoever contradicts his word, for he was the virtuous imam, the consummate leader through whom Allah made the truth manifest when error spread, clarified the path, and suppressed the innovators. May Allah’s mercy be upon that eminent, foremost imam and insightful teacher, and upon all the imams of the Muslims.

“In sum, our doctrine is to acknowledge Allah, His angels, His books, His messengers, and whatever has come from Allah and has been reliably reported from the Messenger of Allah ﷺ; from that we reject nothing. We affirm that Allah is One, unique—”