Sahih Muslim Book 22, Hadith Number 4845.

Chapter : It is meritorious to sacrifice the animal with one’s own hand and so is meritorious the recitation of Bismillah (in the name of Allah) and Takbir (Allah o-Akbar).

‘Aisha reported that Allah’s Messenger (may peace be upon him) commanded that a ram with black legs, black belly and black (circles) round the eyes should be brought to him, so that he should sacrifice it. He said to ‘Aisha: Give me the large knife, and then said: Sharpen it on a stone. She did that. He then took it (the knife) and then the ram; he placed it on the ground and then sacrificed it, saying: Bismillah, Allah-humma Taqabbal min Muhammadin wa Al-i-Muhammadin, wa min Ummati Muhammadin (In the name of Allah, “O Allah, accept [this sacrifice] on behalf of Muhammad and the family of Muhammad and the Umma of Muhammad”).