Virtues and Merits of the Prophet (pbuh) and his Companions
Bukhari :: Book 4 :: Volume 56 :: Hadith 836
Narrated 'Urwa:
That the Prophet gave him one Dinar so as to buy a sheep for him. 'Urwa bought two sheep for him with the money. Then he sold one of the sheep for one Dinar, and brought one Dinar and a sheep to the Prophet. On that, the Prophet invoked Allah to bless him in his deals. So 'Urwa used to gain (from any deal) even if he bought dust. (In another narration) 'Urwa said, "I heard Allah's Apostle saying, "There is always goodness in horses till the Day of Resurrection." (The subnarrator added, "I saw 70 horses in 'Urwa's house.') (Sufyan said, "The Prophet asked 'Urwa to buy a sheep for him as a sacrifice.")