through Muhammad ibn Ishaq ibn Khuzaymah: Muhammad ibn Bashshar (Bundar) narrated to us, saying, “ʿAbd al-Samad narrated to us; ʿUmar ibn Sulaym—who resided among Banu Qushayr—narrated to me; Thawr narrated to me; I asked Ibn ʿUmar …” (the remainder of the report). Al-Maqdisi then commented: “Ibn Khuzaymah recorded it in his Sahih in this very form.” I add: I do not know this Thawr. He is perhaps Thawr ibn ʿUfair al-Sadusi, a transmitter from Abu Hurayrah; he is majhul (unknown), and, as al-Mizan notes, no one other than Ibn Shuqayq narrated from him. Fourth hadith: Muʿayqib related that people asked the Prophet ﷺ about smoothing (i.e., leveling) the ground in the mosque—meaning the pebbles. He replied, “If you must do it, then only once.” Narrated by Muslim 2/74–75; al-Darimi 2/322; Ahmad 3/426, 5/425; also found in al-Bukhari 3/61, Abu Dawud 1/150, al-Nasaʾi 1/177, al-Tirmidhi 2/220 (who declared it sahih), Ibn Majah 1/320 with similar wording, and al-Bayhaqi 2/284–285. Al-Hafiz said in Fath al-Bari: “Note: Limiting the wording to ‘pebbles’ and ‘soil’ merely reflects what normally covered mosque floors at that time; it does not mean that the ruling is inapplicable to other surfaces on which one prays, such as sand, debris, and the like.” There are other reports on the issue, but what has been cited here is sufficient. (1) Reported by Muslim and Abu ʿAwana.