From Sahih Bukhari (Hadith 4021):
Narrated Ibn `Abbas:`Umar said, "When the Prophet (ﷺ) 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 Ma`n bin Adi
Reference: Bukhari 4021