Sahih Bukhari Volume 007, Book 068, Hadith Number 465.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 68. Al-Adha Festival Sacrifice (Adaahi)
Narrated By Anas : The Prophet slaughtered two rams, black and white in color (as sacrifices), and I saw him putting his foot on their sides and mentioning Allah's Name and Takbir (Allahu Akbar). Then he slaughtered them with his own hands.