Musannaf Ibn Abi Shayba 3:5784

Waki’ narrated to us, he said: Sa’id bin ‘Ubayd al-Ta’i narrated to us, from ‘Ali bin Rabi’ah al-Walibi, from al-Rabi’ bin Nadlah, he said: We went out on a journey, and we were twelve or thirteen riders, all of whom had accompanied the Prophet, may God bless him and grant him peace, and fought alongside him. He said: Then the prayer time arrived, and the people deferred to one another, so a young man among them stepped forward and led them in prayer for four rak’ahs. When he finished the prayer, Salman said: "What do we have to do with the 'four-fold' (full prayer)? Half of the 'four-fold' is sufficient for us; we are more in need of lightening [the burden]." They said: "Step forward, O Abu ‘Abd Allah." So he led us in prayer. Then he said: "You are the sons of Ishmael, the leaders, and we are the ministers."