Musnad Ahmad 33:746

Ubaydah narrated to us, Al-Aswad ibn Qays narrated to us, from Nabih al-Anazi, from Jabir ibn Abdullah al-Ansari, who narrated from the Messenger of Allah (may Allah bless him and grant him peace) that he intended to go on a military expedition. He said: "O assembly of the Muhajirun and the Ansar, among your brothers are people who have neither wealth nor kin. So let each one of you take two or three men to himself. For none of us has any mount for his camel except a turn like the turn of one of them." He said: So I took two or three men to myself, and I had nothing but a turn like the turn of one of them from my camel.