Excellence Of Fasting On The Day Of Aashuraa

10 Muharram, 1436

 Besides being a thanks-giving day, "Aashuraa has also been considered by the Shii-'ah group of Muslims as the day of the martyrdom of Imam Husin, the son of Ali, the fourth Caliph of Islam and the grandson of Prophet Muhammad (SAW), and marks the culmination of the ten days' lamentation which is observed every year by them.

On the day of 'Aashuraa, Prophet Muhammad (SAW), enjoin the Muslim to fast (sunnah). Ibnu 'Abbas said: Prophet Muhammad (SAW) came to Madinah and found the Jews observing the fast on the day of 'Aashuraa, so he asked them what was the significance of that day which they were marking with such importance, and they replied:

"It is the great day on which God delivered Moses and his people and drowned the Pharaoh and his people, so Moses observed it as a fast out of gratitude, and we do so also."

"This is a blessed day. On this day Allah (SWT) saved the children of Israel from their enemy (in Egypt) and so Prophet Musa  fasted on this day giving thanks to Allah."

Prophet (SAW) said: "We have more right, and we have a closer connection with Moses than you have," so Prophet Muhammad (SAW) observed it as a fast day himself and gave orders that it should be observed. 
[ Al Bukhari Hadith #1866]

Ibn 'Abbas (R.A) used to say that we should fast on two days: 9th and 10th of Muharram to distinguish ourselves from the Jewish community.
[At Tirmidhi]

Ibn 'Abbas also quoted the Prophet (SAW) said: "If I live next year, I shall also fast on the 9th day."
[Musnad Ahmad ibn Hanbal, Hadith 2002]