Virtues and Merits of the Prophet (pbuh) and his Companions

Bukhari :: Book 4 :: Volume 56 :: Hadith 710

Narrated Salama:

Allah's Apostle passed by some people from the tribe of Aslam practicing archery. He said, "O children of Ishmael! Throw (arrows), for your father was an archer. I am on the side of Bani so-and-so," meaning one of the two teams. The other team stopped throwing, whereupon the Prophet said, "What has happened to them?" They replied, "How shall we throw while you are with Bani so-and-so?" He said, "Throw for I am with all of you."