Abu Dawud Book 9, Hadith Number 2786.
Chapter : The sacrificial animals that are recomended.
Narated By ‘Aisha : The Apostle of Allah (PBUH) ordered a horned ram with black legs, black belly and black round the eyes, and it was brought for him to sacrifice. He said: ‘Aisha, get the knife, then he said: Sharpen it with a stone. So I did. He took it, then taking the ram he placed it on the ground and slaughtered it. He then said: In the name of Allah, accept it for Muhammad, Muhammad’s family and Muhammad’s people. Then he sacrificed it.