Sahih Bukhari Volume 9, Book 89, Hadith Number 287.

Narrated By Ibn ‘Umar : Salim, the freed slave of Abu Hudhaifa used to lead in prayer the early Muhajirin (emigrants) and the companions of the Prophet in the Quba mosque. Among those (who used to pray behind him) were Abu Bakr, ‘Umar, Abu Salama, and Amir bin Rabi’a.