The Day of Tasu'a (Arabic: تاسوعا) refers to the ninth day of Muharram and the day before Ashura.
Several events took place on this day, including: Shemr entrance to Karbala, granting safe passage for the children of ul-Banin Umm, preparation for war, and besieged day. The day is named Abbas ibn Ali, because he was the brave commander of Husayn ibn Ali. Abbas is seen as the embodiment of masculinity, chivalry and loyalty in Shia culture.
The day of Ashura (Arabic: عاشوراء) is the tenth day of Muharram in the Islamic calendar, marking the climax of Muharram reflection.
It is celebrated by Shia Muslims as a day of Husayn ibn martyrdom of Ali, Mohammadan grandson of the Prophet, in the Battle of Karbala, which took place on the 10th day of Muharram of the year 61 of the Islamic calendar (October 2, 680 AD). According to the Sunnah, Mohammadan fasted on this day and asked other people to do the same. Sunni Muslims also celebrate the day, we considered the day that Moses fasted in gratitude to God for the liberation of the Jews from Egypt.