Regarding the manner of sitting for the tashahhud he says: “He mentioned the ḥadith of Waʾil ibn Ḥujr: ‘I saw him moving it while supplicating with it’—reported by Aḥmad.”

I reply: This is a serious lapse, for it gives the impression that none of the authors of the Sunan or the compilers of rigorously authentic works recorded it. In fact, Abu Dawud, al-Nasāʾī, Ibn al-Jārūd in al-Muntaqā, Ibn Khuzayma, and Ibn Ḥibbān all included it in their Ṣaḥīḥ collections, as documented in Sifat al-Ṣalāt, p. 169. Ibn al-Mulqin, al-Nawawī, and Ibn al-Qayyim judged it sound, and it is also cited in Ṣaḥīḥ Abī Dawud, 717.

Note: I have seen some people move their index finger between the two prostrations. Their only proof is that Ibn al-Qayyim mentioned it in Zād al-Maʿād just as he mentioned moving it during the tashahhud. I know of no support for this practice other than an anomalous strand in this very ḥadith of Waʾil, so the matter requires clarification. I say:

This ḥadith is transmitted by ʿĀṣim ibn Kulayb from his father, from Waʾil. Several trustworthy narrators report it from ʿĀṣim, and they all agree on the mention of raising the index finger, yet they fall into three groups concerning the exact point at which the finger is raised:

1. Those who speak in general terms and do not specify when it is raised—among them are Zāʾidah ibn Qudāmah, Bishr ibn al-Mufaḍḍal, Sufyān al-Thawrī, and Sufyān ibn ʿUyaynah, although the context of their reports suggests that it occurs during the tashahhud.

2. Those who explicitly state that it is during the sitting of the tashahhud—among them Ibn ʿUyaynah in a report recorded by al-Nasāʾī 1/173, Shuʿbah in Ibn Khuzayma’s Ṣaḥīḥ no. 697, and Aḥmad 4/319.