Tomorrow is the tenth of Almuharram, the month of the first Islamic calendar. This date marks the day that Prophet Musa (peace be upon him) was chased by Pharaoh. When they reached the sea, the followers of Prophet Musa were desperate and they told him that Pharaoh would eliminate them. God told Musa to hit the sea with his stick and it was divided into two divisions. They were like two great hills. A path was made between them, and the followers of Prophet Musa passed.
When Pharaoh came in trying to reach them the two hills were back and he was drowned with his army. Prophet Musa and his followers were saved. On the same day, there was the battle of Karbalaa. Alhussein Ibn Ali, the grandson of Prophet Muhammad (peace and blessings of Allah be upon him) was martyred along with his supporters. We fast tomorrow. It is not obligatory. For more information on Ashura, please, look at my previous blog on the topic.