Zayd bin al-Hasan bin Ali narrates from his father, Sayyiduna al-Hasan bin Ali (may Allah be pleased with them both), that the Messenger of Allah (peace and blessings be upon him) commanded us on the two Eids to wear the finest clothing available to us, to apply the best perfume available to us, and to sacrifice the fattest animal available to us, a cow on behalf of seven people and a camel on behalf of ten people (to be sacrificed), and to pronounce the takbir aloud while tranquillity and dignity remain upon us. Had it not been for the unknown condition of Ishaq bin Buzurj, I would have ruled this hadith to be sahih (authentic).