Sayyiduna Ibn Abbas (may Allah be pleased with them) narrated that when the Prophet (peace and blessings of Allah be upon him) came to Madinah (in the second year), he saw the Jews fasting on the day of Ashura. He inquired from them about the reason for this. They replied that this is a good day; on this day Allah Almighty saved the Children of Israel from their enemy (Pharaoh), so Musa (peace be upon him) fasted on this day. The Prophet (peace and blessings of Allah be upon him) said, "We are more deserving of following Musa (peace be upon him) than you." Thus, he fasted on that day and ordered his Companions to do so as well.

Sayyiduna Abu Musa (may Allah be pleased with him) narrated that the Jews considered the day of Ashura as a festival, so the Messenger of Allah (peace and blessings be upon him) said: "You should also fast on this day."

Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated that I did not see the Prophet Muhammad (peace and blessings be upon him) deliberately fasting on any day, considering it superior to other days, except for the day of Ashura and this month of Ramadan.

Sayyiduna Salamah bin Akwa’ (may Allah be pleased with him) narrated that the Prophet Muhammad (peace and blessings be upon him) sent a man on the day of ‘Ashura to announce that whoever has eaten should complete (the fast) for the rest of the day (i.e., remain in the state of fasting until sunset), or (he said) should fast, and whoever has not eaten should (begin to) fast and not eat.

Sayyidah Rubayyi’ bint Mu’awwidh (may Allah be pleased with her) said that on the morning of ‘Ashura, the Messenger of Allah (peace and blessings be upon him) sent word to the neighborhoods of the Ansar that whoever among them had eaten or drunk in the morning should complete the rest of the day (like a fasting person), and whoever had not eaten or drunk should observe the fast. Rubayyi’ said: After that (after the fasting of Ramadan was made obligatory), we would still fast on that day and also make our children fast. We would give them a toy made of wool to keep them occupied, and when any of them cried for food, we would give them that toy until it was time to break the fast.

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).

Muhammad bin ‘Abbad says: I asked Sayyiduna Jabir (may Allah be pleased with him),“Did the Prophet (peace and blessings be upon him) forbid fasting on Friday?”He replied:“Yes.”

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrated that I heard the Prophet (peace and blessings of Allah be upon him) say: No person should fast on Friday unless he fasts a day before it or a day after it.