Question:
What are the days one should fast in Muḥarram?
Answer:
Jazākumullāhu Khayran/ Thank you for your question.
In general, there is merit for fasting any day in the month of Muḥarram. However, there is strong recommendation for one to fast on the 10th of Muḥarram. There is also specific instruction for the one who is fasting on the 10th to include one additional day of fasting, either on the 9th or 11th to make the islamic fasting of Muḥarram distinct from other communities.
“The best fasts besides the month of Ramadān, is the fasting in Allāh’s month of Muḥarram ” (Ṣaḥīḥ Muslim)
“The one that keeps a fast in the month of Muḥarram will receive the reward of thirty fasts for each fast (in this sacred month).” (Ṭabrānī)
‘The Messenger of Allāh (peace and blessings upon him) commanded us to fast ‘Ᾱshūra’, the tenth day of Muḥarram.’ (Tirmidhī)
“When the Messenger of Allāh (peace and blessings upon him) fasted on ‘Ᾱshūra’and commanded the Muslims to fast as well, they said, ‘O Messenger of Allāh, it is a day that is venerated by the Jews and Christians.’ The Messenger of Allāh said, ‘If I live until the next year, we will fast on the ninth day too.’” (Ṣaḥīḥ Muslim)
And Allāh Knows Best