al-Tirmidhi (2/276) and Ibn Majah (1/351) also transmitted it through the route of Abu Ahmad al-Zubayri: “Sufyan narrated to us, from Abu Ishaq, from Mujahid, from him.” This isnad is composed of transmitters accredited by the two Shaykhs. al-Tirmidhi remarked: “A hasan hadith. We do not know it narrated by al-Thawri from Abu Ishaq except through Abu Ahmad; what people commonly know is the narration of Israil from Abu Ishaq. Abu Ahmad has likewise reported this hadith from Israil, and Abu Ahmad al-Zubayri is a trustworthy memoriser.” The learned annotator comments: “It seems al-Tirmidhi was pointing to a possible flaw in the chain—namely, that most transmitters narrate it from Israil on the authority of Abu Ishaq, whereas only Abu Ahmad narrates it from al-Thawri. Yet this is not a defect: when the reporter is reliable there is no problem with the hadith being transmitted from both al-Thawri and Israil from Abu Ishaq, so long as trustworthy narrators convey it. Abu Ahmad is reliable; therefore his report from al-Thawri strengthens the report of others from Israil. Moreover, he himself also transmitted it from Israil, so he preserved what they preserved and added material they did not relate—or that has not reached us from them.” End quote. This is the correct assessment. In addition, I have found a corroborating chain for Israil: al-Maqdisi recorded it in al-Mukhtara through al-Tabarani → al-Dabbari → Abd al-Razzaq: “Sufyan (al-Thawri) narrated it to us,” and he provides another route as well. He said: “The hadith of Ibn Umar is sahih and without defect; the version transmitted by Israil contains an extra wording.” This will be cited later under (Sunnah of Maghrib). Third: from Ibn Masud who said: “I cannot count how many times I heard the Messenger of Allah ﷺ recite in the two rakahs after Maghrib and in the two rakahs before Fajr: ‘Qul ya ayyuha’l-kafirun’ and ‘Qul huwa Allahu ahad.’”