Urwah narrated that among those of the Ansar who pledged allegiance to the Messenger of Allah (peace and blessings be upon him) at al-Aqabah, then from Banu al-Harith bin al-Khazraj, is the name of Sayyiduna Sa'd bin al-Rabi' bin Amr (may Allah be pleased with him). He was a naqib (chief representative), and he also took part in Badr.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5376