Imam Ahmad relates in the Musnad: Ismaʿil narrated to us, Ayub narrated to us, from Muhammad, from ʿAmr ibn Wahb al-Thaqafi, who said:
“We were in the company of al-Mughira ibn Shuʿba when he was asked, ‘Did anyone from this community ever lead the Prophet ﷺ in prayer other than Abu Bakr?’ He replied, ‘Yes.’ He then explained that the Prophet ﷺ performed wuduʾ (ablution), wiped over his khuffayn (leather socks) and his turban, and that he prayed behind ʿAbd al-Rahman ibn ʿAwf—while I was with him—for one rakʿa (unit) of the dawn prayer. We then completed the rakʿa for which we had been preceded. (1)
A parallel report is transmitted by Humayd al-Tawil, from Bakr ibn ʿAbd Allah, from Hamza ibn al-Mughira, from his father. (2)
Ibrahim ibn Saʿd narrates—from his father, from his grandfather—that the Messenger of Allah ﷺ came upon ʿAbd al-Rahman ibn ʿAwf while he was leading the people in prayer. ʿAbd al-Rahman wished to step back, but the Prophet ﷺ gestured to him to remain where he was, and he continued the prayer; the Messenger of Allah ﷺ then completed the prayer behind ʿAbd al-Rahman. (3)
(1) Reported by Ahmad, 4/249–251; al-Nasai, 1/77 (Purification, “How to wipe over the turban”). Also transmitted by Muslim, no. 81 (Purification) through Bakr b. Abd Allah al-Muzani → Urwa b. al-Mughira → al-Mughira b. Shuʿba; by Abu Dawud, no. 151, through Isa b. Yunus → his father → al-Shaʿbi → Urwa b. al-Mughira → al-Mughira; by al-Bukhari in abridged form, no. 182 (Wudu) through Saʿd b. Ibrahim → Nafiʿ b. Jubayr → Urwa b. al-Mughira → al-Mughira, and likewise—also abbreviated—in nos. 203, 206, 363, 388, 2918, 4421, 5798, 5799. Ibn Majah, no. 545 (Purification), gives the same shortened version. A fuller wording appears in Ibn Saʿd, 3/1/91; Ibn Hajar, al-Isaba, 6/312; and al-Tayalisi, nos. 223, 691.
(2) Reported by Ahmad, 4/248, and by Ibn Majah, no. 1236 (Iqama, “The Prophet’s prayer behind one of his community”), both through Humayd → Bakr b. Abd Allah → Hamza b. al-Mughira b. Shuʿba → his father; the isnad is sound. Also recorded by al-Fasawi, 1/398-399, and by Muslim, no. 274 (Purification, “Wiping over the forelock and turban”) through Humayd → Bakr b. Abd Allah al-Muzani → Urwa b. al-Mughira → his father.
(3) Cited by Ibn Hajar in al-Matalib al-ʿAliya, no. 415, who attributes it to Abu Yaʿla.