Jabir b. Samura said, “God’s messenger used to command us to observe the day of ‘Ashura’ as a fast, urge us to observe it and pay attention to us when it came; but when Ramadan was made obligatory he neither commanded nor forbade us to observe it, nor did he pay attention to us when it came.”
Umm Salama said that God's messenger used to fast on Saturdays and Sundays more than on other days, and he used to say, “They are days of festival for the polytheists, and I like to act contrary to them.”
Narrated Hafsa said there were four things the Prophet never omitted:
fasting on ‘Ashura’, the first ten days of Dhul Hijja* and three days every month, and praying two rak'as before dawn.
*The Arabic has simply 'the ten', to be understood as translated above.
Ibn ‘Abbas said that God’s messenger came to Medina and found the Jews observing the fast on the day of ‘Ashura’, so he asked them what was the significance of that day which they were observing and they replied, “It is a great day on which God delivered Moses and his people and drowned Pharaoh and his people; so Moses observed it as a fast out of gratitude, and we do so also.” He said, “We have more right, and we have a closer connection with Moses than you have,” so God’s messenger observed it as a fast himself and gave orders that it should be observed.
