Muhammad bin Abdullah bin Numayr (may Allah have mercy on him) relates: "(Regarding) Abu Sa'id bin al-Mu'alla, a man from among his descendants told me that his name was Rafi' bin al-Mu'alla al-Ansari, and that he was from Banu Khubayb bin Abd Harithah bin Malik."
Hadith Referenceالمعجم الكبير للطبراني / باب الراء / 4447