Sayyiduna Ka'b bin Malik (may Allah be pleased with him) said: We set out for the Hajj in which we pledged allegiance to the Messenger of Allah (peace and blessings be upon him) at Aqabah, and at that time the naqibs (leaders) of Banu Sa'idah were Sayyiduna Sa'd bin Ubadah (may Allah be pleased with him) and Mundhir bin Amr (may Allah be pleased with him).
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5335