Muslim and al-Nasaʾi also transmit the report through Sufyan, from Muslim b. Abi Maryam, with a similar wording. Sufyan said: “Yahya b. Saʿid used to relate it to us from Muslim, and later Muslim himself narrated it to me.” Ismaʿil b. Jaʿfar likewise reports it from Muslim b. Abi Maryam, and that version contains the third additional phrase. This route is recorded by Abu ʿAwana (2/226), al-Nasaʾi (no. 173), and al-Bayhaqi (2/132); it is sound and firmly established. There is a second chain: Ahmad (2/119) relates—“Muhammad b. ʿAbd Allah Abū Ahmad al-Zubayri told us; Kathir b. Zayd narrated to us from Nafiʿ, who said: Whenever ʿAbd Allah b. ʿUmar sat during the prayer he would place his hands on his knees, point with his finger and follow it with his gaze, then say: The Messenger of Allah ﷺ said, ‘It (the index finger) is more crushing to Satan than iron.’” This isnad is hasan, or very nearly so: all the transmitters are reliable narrators of the Six Books except Kathir b. Zayd, who is saduq but makes mistakes, as stated in Taqrib. Through this same Kathir b. Zayd it is also reported by al-Tabarani in al-Duʿa (fol. 73/1 = pp. 205, nos. 642–643) and by al-Bazzar, as cited in Majmaʿ (2/140), where he remarks: “Ibn Hibban declared him trustworthy, while others considered him weak.” I add: The marfuʿ portion is likewise narrated by al-Ruyani in his Musnad (249/2 = 290/1439) and by al-Bayhaqi. (*) Shaykh — in the printed edition of al-Sifa — also attributes it to Abu Jaʿfar al-Bakhtari in al-Amali (60/1) and to ʿAbd al-Ghani al-Maqdisi in al-Sunan (12/2) with a hasan chain.