Volume 3 · Book 34 · Hadith 424
Narrated 'Abdullah bin 'Abbas: Once Allah's Apostle passed by a dead sheep and said to the people, "Wouldn't you benefit by its skin?" The people replied that it was dead. The Prophet said, "But its eating only is illegal."
— Sahih Bukhari, Volume 3, Book 34: Sales and Trade, Hadith #424