Why the Prophet ﷺ Wanted Muslims to Fast One Extra Day Before Ashura

The Prophet ﷺ fasted Ashura every year after arriving in Madinah. But in his final year, he said something that changed how this fast is observed to this day — he expressed an intention to add a second day, one he never lived to carry out himself.

Ashura Already Existed Before Islam

When the Prophet ﷺ arrived in Madinah, he found that the Jewish community there already observed a fast on the 10th of Muharram, commemorating Allah's deliverance of Musa (AS) and the Children of Israel from Pharaoh. Recognizing the legitimacy and significance of this day, the Prophet ﷺ adopted the fast and instructed Muslims to observe it as well.

The Statement That Changed the Practice

This is a remarkable detail preserved in the hadith literature — a clear statement of intention from the Prophet ﷺ himself, left unfulfilled only because his life ended before the next Muharram came. Scholars have treated this statement as a strong basis for recommending the 9th of Muharram, known as Tasua, be fasted alongside the 10th.

Why Add a Second Day?

Scholars offer a few explanations for why the Prophet ﷺ wanted to add the 9th. One explanation is to distinguish the Muslim observance of this day from that of other religious communities who fasted only the 10th, giving the practice its own distinct Islamic character rather than mirroring another tradition exactly. Another explanation suggests fasting the 9th provides a safeguard, in case of any error in calculating the exact lunar date of the 10th — ensuring the core day of Ashura is reliably covered either way.

Some Scholars Add a Third Day

A number of scholars also mention the possibility of fasting the 11th of Muharram in addition to the 9th and 10th, based on some narrations, as a way of further distinguishing the practice. While the two-day combination of Tasua and Ashura is the most strongly emphasized, fasting three consecutive days is considered an additional, optional layer of the same Sunnah for those who wish to do more.

What This Means for How You Plan It

Rather than treating Ashura as a single isolated date to remember, the stronger application of the Sunnah is to plan for two consecutive fasting days — the 9th and 10th of Muharram. This requires a bit more intentionality: checking the Islamic calendar in advance, marking both dates, and preparing for back-to-back fasting rather than a single spontaneous fast.

A Reminder About Following the Hijri Calendar

Because the Islamic calendar is lunar, the Gregorian dates for Muharram shift each year. Relying on a verified Islamic calendar or local moon-sighting announcements, rather than assuming the date based on the previous year, is necessary to fast on the correct days.

Conclusion

The Prophet ﷺ had every intention of fasting two days for this occasion, not one — a plan interrupted only by the end of his life. Following through on that unfulfilled intention, by fasting both Tasua and Ashura, is one of the more meaningful ways to connect to a Sunnah the Prophet ﷺ himself wanted to establish but did not get the chance to complete.