Abu Ubayd, the freed slave of Sayyiduna Abd al-Rahman bin Awf (may Allah be pleased with him), narrates that he attended the Eid with Sayyiduna Umar bin al-Khattab (may Allah be pleased with him). He led the prayer before the sermon, without adhan or iqamah, then delivered the sermon and said: "O people! The Messenger of Allah (peace and blessings be upon him) forbade you to fast on these two days. One of them is the day of Eid al-Fitr, the day you break off from your fasting, and the other is the day on which you eat (the meat) of your sacrifices."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8457