Sahih Bukhari Volume 5, Book 57, Hadith Number 15.

Narated By Abu Huraira : I heard Allah’s Apostle saying, “While a shepherd was amongst his sheep, a wolf attacked them and took away one sheep. When the shepherd chased the wolf, the wolf turned towards him and said, ‘Who will be its guard on the day of wild animals when nobody except I will be its shepherd. And while a man was driving a cow with a load on it, it turned towards him and spoke to him saying, ‘I have not been created for this purpose, but for ploughing.” The people said, “Glorified be Allah.” The Prophet said, “But I believe in it and so does Abu Bakr end ‘Umar.”