Commercial Transactions (Kitab Al-Buyu)
Dawud :: Book 22 : Hadith 3378
Narrated Urwah ibn AbulJa'd al-Bariqi:
The Prophet (peace_be_upon_him) gave him a dinar to buy a sacrificial animal or a sheep. He bought two sheep, sold one of them for a dinar, and brought him a sheep and dinar. So he invoked a blessing on him in his business dealing, and he was such that if had he bought dust he would have made a profit from it.