It is extremely weak and may not be adduced as evidence, for al-Harith al-Aʿwar is judged weak by unanimous agreement of the hadith critics and is known for fabricating reports. In addition, Abu Dawud said of this narration: “Abu Ishaq heard only four hadiths from al-Harith, and this is not one of them.” Al-Hafiz continued: “A sound report has been transmitted from Abu ʿAbd al-Rahman al-Sulami who said that ʿAli declared: ‘If the imam asks to be prompted, then prompt him.’” Al-Khattabi explained: “That is, if he falters in the recitation, supply it for him.” The hadith of Ibn ʿUmar has another supporting chain, recorded by al-Daraqutni (no. 153) and by al-Tabarani in al-Awsat—as cited in Majmaʿ (2/69)—but its isnad is weak. Al-Daraqutni (no. 153) and al-Hakim (1/276) also narrated, through Yahya b. Ghilan, from ʿAbd Allah b. Baziʿ, from Humayd, from Anas: “In the time of the Messenger of Allah we used to prompt the imams during prayer.” Al-Hakim graded it sahih and said, “ʿAbd Allah b. Baziʿ is reliable,” a judgment echoed by al-Dhahabi. I say: Not so. Concerning this ʿAbd Allah b. Baziʿ, al-Daraqutni called him “lenient” (that is, weak); al-Saji and Ibn ʿAdi said, “He is not a proof”; and al-Bayhaqi stated in al-Sunan (6/108) that “he is weak.” Al-Dhahabi placed him in al-Mizan, cited the remarks of al-Daraqutni and Ibn ʿAdi without further comment, and then quoted for him a repudiated (munkar) report.