Abu Dawud Book 3, Hadith Number 1716.
Chapter : Not known.
Narated By Al-Mundhir ibn Jarir : I accompanied Jarir at Bawazij. The shepherd brought the cows. Among them there was a cow that was not one of them. Jarir asked him: What is this? He replied: This was mixed with the cows and we do not know to whom it belongs. Jarir said: Take it out. I heard the Apostle of Allah (PBUH) say: No one mixes a stray animal (with his animals) but a man who strays from right path.