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
Abu Ubayd (may Allah have mercy on him) said: I was present at Eid with Sayyiduna Umar bin al-Khattab (may Allah be pleased with him), and he began with the prayer before the sermon. Then he said that the Messenger of Allah (peace and blessings be upon him) "forbade fasting on these two days: as for the Day of Adha, on it you eat from your sacrifices; and as for the Day of Fitr, it is the day of breaking your fasts."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8249
Hakim bin Abi Harrah said that he heard a man asking Abdullah bin Umar (may Allah be pleased with them both) about vowed fasts: a man names a day and vows that such-and-such a day will not come except that he is fasting on it, and that day turns out to be the day of Eid al-Adha or Eid al-Fitr. So Ibn Umar (may Allah be pleased with them both) said: "Indeed in the Messenger of Allah you have an excellent example" [Al-Ahzab: 21]; the Messenger of Allah (peace and blessings be upon him) did not fast on the Day of Adha or the Day of Fitr, nor did he order fasting on them.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8250
Ka'b bin Malik (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) sent him and Aws bin al-Hadathan (may Allah be pleased with them both) during the days of Tashriq to announce: "None will enter Paradise except a believer, and the days of Mina are days of eating and drinking."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8251
The freed slave of Aqil bin Abi Talib (may Allah be pleased with him) narrates: Abdullah bin Amr (may Allah be pleased with them both) and I went to Amr bin al-As (may Allah be pleased with him); this was on the first or second day after Eid al-Adha. Amr (may Allah be pleased with him) placed food before him, and Abdullah (may Allah be pleased with them both) said: I am fasting. So Amr (may Allah be pleased with him) said to him: "Break your fast; these are among the days on which the Messenger of Allah (peace and blessings be upon him) used to order us to break the fast and forbid us from fasting." Then Abdullah (may Allah be pleased with them both) broke his fast and ate, and we ate with him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8252