I was with my father at al-Qaa near Namirah when a group of riders passed by, and there was the Messenger of Allah ﷺ standing in prayer. I kept looking at the whiteness of his armpits whenever he prostrated.
حدثنا أبو كريب حدثنا أبو خالد الأحمر عن داود بن قيس
كنت مع أبي بالقاع من نمرة فمرت ركبة فإذا رسول الله ﷺ قائم يصلي قال فكنت أنظر إلى عفرتي إبطيه إذا سجد أي بياضه
[Sahih]. Ibn Majah also recorded it in Iqamat al-Salawat, Chapter on sujud, no. 881, and Nasai, 2/213, no. 1109, from the hadith of Dawud bin Qays, with this wording.On this subject there are also narrations from Ibn Abbas [Abu Dawud, no. 899], Ibn Buhayna [Bukhari, no. 390, and Muslim, no. 495], Jabir [Ahmad, 3/294, 295, and Ibn Khuzayma, no. 649], Ahmar bin Jaz [Abu Dawud, no. 900], Maymuna [Muslim, 496/237], Abu Humayd [coming up, no. 304], Abu Usayd [the same reference], Abu Masud [Ahmad, 5/272], Sahl bin Saad and Muhammad bin Maslama [Abu Dawud, no. 734], Bara bin Azib [Abu Dawud, no. 806], Adi bin Amira [Ahmad, 4/93, and Ibn Khuzayma, no. 650], and Ayesha [we did not find this, though it may be a reference to the hadith of Muslim, no. 498].