Sayyiduna Umar (may Allah be pleased with him) said: "These are two days whose fasting the Messenger of Allah (peace and blessings of Allah be upon him) forbade: the day of breaking the fast after (the fasts of) Ramadan (i.e., Eid al-Fitr), and the other day on which you eat the meat of your sacrifice (i.e., the day of Eid al-Adha)."

Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) said: "Do not fast on the days of Eid al-Fitr and Eid al-Adha."

Ziyad bin Jubair (may Allah have mercy on him) narrated that a man came to Sayyiduna Ibn Umar (may Allah be pleased with them) and said that a person made a vow to fast for one day, then thought that it would be a Monday, and by coincidence, that day turned out to be Eid. Sayyiduna Ibn Umar said that Allah Almighty has commanded the fulfillment of vows, and the Noble Prophet (peace and blessings of Allah be upon him) has forbidden fasting on that day (by Allah’s command).