Ibn Shihab narrated that among those of the Ansar who took part in the Pledge of al-Aqabah, then from Banu Amr bin Awf, is the name of Sayyiduna Sa'd bin Khaythamah (may Allah be pleased with him). He was a naqib (chief representative).
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5391