“Abu Dawud recorded it with a good isnad and did not judge it weak; and his principle is that whatever he leaves without a negative ruling is, in his view, hasan (acceptable).” I reply: this rule popularly ascribed to Abu Dawud does not always hold, according to the critical scholars. There are many reports on which Abu Dawud is silent yet they deem weak; indeed, al-Nawawi himself says about a hadith he cites in al-Majmu from the Sunan: “Abu Dawud merely kept silent about it because its weakness is obvious.” This particular hadith is plainly weak, for it comes through Marwan ibn Muawiyah → Yahya al-Kahili → al-Musawwar. This Yahya is Ibn Kathir al-Kahili, and, as al-Mizan notes, no one narrated from him except this Marwan. Al-Mizan adds, “He was declared reliable,” but this points to the fragility of that verdict, for it is the sole authentication of Ibn Hibban, who is well-known for leniency—often accrediting narrators whom others regard as unknown. Al-Dhahabi continues: “Abu Hatim said: ‘An ordinary shaykh’; al-Nasa i said: ‘Weak.’” Ibn Hajar in al-Taqrib writes: “Soft in hadith.” In Tahdhib he adds, quoting Amir Ibn Makula, that the name al-Musawwar is pronounced with a closed m, open s, and doubled w, then relates Bukhari’s comment: “He has one hadith on the prayer, unknown”—meaning this very report. As for the narration transmitted by Abd al-Razzaq in his Musannaf and by Abu Dawud in his Sunan through Abu Ishaq → al-Harith → Ali, marfuʿ: “O Ali, do not prompt the imam in the prayer,” it is weak. Al-Nawawi said: