Muharram (Arabic: محرم) is the first month of the Islamic calendar. It is one of the four sacred months. The Islamic calendar is lunar. The month of Muharram is also associated with many auspicious events in Islamic history. Allah is supposed to have created the heavens and the earth on this blessed day. On this day He give His infinite blessings and bounties to many of His Prophets and delivered them from the clutches of their enemies.
Allah created Hazrat Adam in this month and pardoned him of his mistake. Hazrat Noah's Ark landed successfully on Mount Judi during this time centuries ago. God is also said to have saved Hazrat Ibrahim from fire and rescued Hazrat Musa from the Pharaoh during the month of Muharram.
The tenth day of Muharram or Ashura is of supreme importance for Shia Muslims as they celebrate the death anniversary of Hussain, the grandson of the Prophet Muhammad.
So it is recommended to fast on the 10th of Muharram and the 9th along with it as well. Fasting is advocated in the month of Muharram. The Prophet is believed to have said: "The best fasts after the fasts of Ramadan are those of the month of Muharram." Although the fasts of the month of Muharram are not obligatory, yet one who fasts in these days out of his own will is entitled to a great reward by Allah Almighty. Fasting on the tenth day of Muharram, called Ashura, is particularly important, as it supposed to lead to great rewards. A person does not have to fast for the whole month. On the contrary, each fast during this month has merit.