Sahih Bukhari
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
Volume: 005 / Book Number: 059 / Hadith Number: 356
Narrated Ibn Abbas:
'Umar said, "When the Prophet died I said to Abu Bakr, 'Let us go to our Ansari brethren.' We met two pious men from them, who had fought in the battle of Badr." When I mentioned this to Urwa bin Az-Zubair, he said, "Those two pious men were 'Uwaim bin Sa'ida and Manbin Adi."