Majma al-Zawaid — Hadith 5967

Sayyiduna Abu Rafi' (may Allah be pleased with him), the freed slave of the Prophet (peace and blessings be upon him), states: When the Prophet (peace and blessings be upon him) offered sacrifice, he would buy two fat rams with horns, whose white predominated over the black (or which were entirely white). When he finished the prayer, he delivered the sermon; then he came to one of the two while he was at the Eid prayer ground, slaughtered it, and then said: "O Allah! This is on behalf of every person of my entire Ummah who bears witness to Your Oneness (tawhid) and bears witness that I have conveyed (the message)." Then the other animal was brought, and he slaughtered it and then said: "O Allah! This is on behalf of Muhammad and the family of Muhammad." He fed the meat of both to the poor, and he and his household also ate of it. The narrator states: Then several years passed in which no one of Banu Hashim would offer sacrifice, because the Messenger of Allah had fulfilled this duty on our behalf.
Al-Bazzar recorded it, Ahmad recorded something similar, and Tabarani recorded something similar in al-Mu'jam al-Kabir.