Firstly:
Fasting the day of ‘Ashoora’ does expiate for the past year, because the Prophet (peace and blessings of Allaah be upon him) said: “Fasting the day of ‘Arafah I hope Allaah will expiate thereby for the year before it and the year after it, and fasting the day of ‘Ashoora’ I hope Allaah will expiate thereby for the year that came before it.” Narrated by Muslim, 1162. This is by the bounty that Allaah bestows upon us, whereby fasting one day expiates for the sins of a whole year. And Allaah is the Owner of great bounty.
The Prophet (peace and blessings of Allaah be upon him) used to be very keen to make sure he fasted on the day of ‘Ashoora’ because of its great status. It was narrated that Ibn ‘Abbaas (may Allaah be pleased with him) said: I never saw the Prophet (peace and blessings of Allaah be upon him) so keen to make sure he fasted any day and preferring it over another except this day, the day of ‘Ashoora’, and this month – meaning Ramadaan. Narrated by al-Bukhaari, 1867.
What is meant by being keen to make sure he fasted it is so as to earn its reward.
