^Ashura' day lies on the 10th day of Muharram. Fasting the day of ^Ashura' has been unanimously agreed upon by scholars of Islam to be a sunnah deed.
Many great events in the history of Islam happened on the day of ^Ashura'. Some of which were as follows :
On this day, Allah saved Prophet Moses from the evil Pharaoh who drowned also on that day.
Allah accepted the repentance of Adam after he committed the small sin when he ate from the forbidden tree in Paradise. This was a small sin, however, not one that shows low self-respect.
Also on the day of ^Ashura' the Arc of Prophet Noah landed safely on the Mount of Al-Judiyy in Iraq after the flood .Al-Hussayn son of Imam ^Aliyy was martyred on that day and the battle of “Dhatur-Riqa^” took place on the tenth of Muharram as well.
The validity of fasting ^Ashura' started when Prophet Muhammad arrived at Al-Madinah .He saw some Jews fasting ^Ashura'. When he inquired about the reason behind their fasting, they explained to him that this day is special to them because on that day Allah gave Moses victory over Pharaoh.
Upon hearing this, Prophet Muhammad said: “We associate with Moses more than you do”. The Prophet said this because Moses was Muslim as all the prophets, and we are more deserving of rejoicing his victory.
Then the Prophet continued by urging Muslims to fast the day of ^Ashura' and the day before by saying:
If I were to remain alive until Muharram of next year I will fast the ninth and the tenth of that month. Prophet Muhammad specified two days of fasting rather than the single day the Jews used to fast for two reasons:
One reason is to differ from the Jews while the other is to assure that they did not miss fasting the tenth of Muharram, due to the possibility of an error in confirming the beginning of Muharram.
In the end, we ask Allah to enable us to adhere to the methodology of our Prophet by fulfilling his sunnah and to keep us steadfast on the path of knowledge and obedience Ameen.