It is narrated from Sayyidah Aishah (may Allah be pleased with her) that on the day of Badr the Messenger of Allah (peace and blessings be upon him) made the battle-cry of the Muhajirun "Bani Abd al-Rahman" (sons of Abd al-Rahman), that of the Aws "Bani Abdillah" (sons of Abdullah), and that of the Khazraj "Bani Ubaydillah" (sons of Ubaydullah).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 13051