Abu Ubayd, the freed slave of Ibn Azhar, said: I was present at Eid with Sayyiduna Umar bin al-Khattab (may Allah be pleased with him). He came and led the prayer, then addressed the people and said: "The Messenger of Allah (peace and blessings be upon him) forbade fasting on these two days: this day is the day of breaking your fasts, and the other is the day on which you eat from your sacrifices."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8248