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), and at that time the naqibs (chief representatives) of Banu al-Khazraj were Sayyiduna Abdullah bin Rawahah (may Allah be pleased with him) and Sayyiduna Sa'd bin al-Rabi' (may Allah be pleased with him).
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5383