Abdullah bin Muhammad bin Aqil bin Abi Talib narrates from Ali bin al-Husayn (may Allah have mercy on him) concerning the saying of Allah Almighty: "For every nation We have appointed a rite which they perform" [Surah al-Hajj: 67]; he said: (It means) a slaughter which they perform. Abu Rafi' (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) bought two rams that were greyish-white, horned and fat. After the sermon and the prayer, he (peace and blessings be upon him) slaughtered one ram with a knife with his own hand, then said: "O Allah, this is on behalf of my Ummah, those who testify to Your Oneness and to my having conveyed (the message)." Then the other ram was brought, and he (peace and blessings be upon him) slaughtered it, then said: "This is on behalf of Muhammad (peace and blessings be upon him) and the family of Muhammad." Then he fed the meat to the poor, and he himself and his family also ate of it. We remained for years, Allah having spared us the expense and the burden, and none of Banu Hashim offered a sacrifice.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19009