General Behavior (Kitab Al-Adab)
Dawud :: Book 41 : Hadith 5104
Narrated AbuUqbah:
AbdurRahman ibn AbuUqbah quoted his father AbuUqbah who was a client from the people of Persia as saying: I was present at Uhud along with the Apostle of Allah (peace_be_upon_him), and on smiting one of the polytheists I said: Take this from me who is the young Persian. The Apostle of Allah (peace_be_upon_him) then turned to me and said: Why did you not say: Take this from me who is the young Ansari?