In the name of Allah, the Gracious, the Merciful
There is great virtue in increasing our voluntary fasts during the sacred month of Al-Muharram, and specifically fasting on the day of Ashura, which is the tenth day of Al-Muharram. Not only will a Muslim be rewarded greatly for fasting, but also fasting the day of Ashura will expiate the minor sins committed in the previous year.
It is explicit from the Prophet (ṣ) that best month for voluntary fasting is the month of Al-Muharram. This month is the first of the Hijri calendar and one of the four traditionally sacred months.
Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:
أَفْضَلُ الصِّيَامِ بَعْدَ شَهْرِ رَمَضَانَ صِيَامُ شَهْرِ اللَّهِ الْمُحَرَّمِ
The best fast after the month of Ramadan is fasting in the month of Allah, al-Muharram.
Source: Ṣaḥīḥ Muslim 1163, Grade: Sahih
The most important day to fast in Al-Muharram is the day of Ashura, as the Prophet (ṣ) was keen to fast this day as much as he was to fast in Ramadan.
‘Ubaydallah reported: Ibn Abbas, may Allah be pleased with him, said:
مَا رَأَيْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَتَحَرَّى صِيَامَ يَوْمٍ فَضَّلَهُ عَلَى غَيْرِهِ إِلَّا هَذَا الْيَوْمَ يَوْمَ عَاشُورَاءَ وَهَذَا الشَّهْرَ يَعْنِي شَهْرَ رَمَضَانَ
I did not see the Prophet, peace and blessings be upon him, as eager to fast a day and preferring it over others except for this day of Ashura and this month of Ramadan.
Source: Ṣaḥīḥ al-Bukhārī 1902, Grade: Muttafaqun Alayhi
The day of Ashura is distinguished in Al-Muharram as the day Allah saved Moses, upon him be peace, and the Israelites from Pharaoh, when Allah miraculously parted the sea for them and drowned the pursuing army.
Ibn Abbas reported: The Messenger of Allah, peace and blessings be upon him, came to Medina and he found the Jews fasting on the day of Ashura. The Prophet said:
مَا هَذَا الْيَوْمُ الَّذِي تَصُومُونَهُ
What is this day you are fasting?
They said, “This is a great day in which Allah saved Moses and his people, and he drowned Pharaoh and his people. Moses fasted on it due to gratitude, so we also fast on it.” The Prophet said:
فَنَحْنُ أَحَقُّ وَأَوْلَى بِمُوسَى مِنْكُمْ
We are more deserving and are closer to Moses than you.
Source: Ṣaḥīḥ al-Bukhārī 3216, Grade: Muttafaqun Alayhi
The day of Ashura corresponds to Yom Kippur in Judaism. The meaning of Muslim believers (not just any Muslim) being closer to Moses, upon him be peace, is that true Muslims adhere to the divine revelation as it was communicated to him, while over time Jewish theology had strayed from his original message.
Al-Harawi commented on this tradition, writing:
أَيْ بِمُتَابَعَتِهِ يعنى موسى عليه السلام فَإِنَّا مُوَافِقُونَ لَهُ فِي أُصُولِ الدِّينِ وَمُصَدِّقُونَ لِكِتَابِهِ فِي تَبْيِينِ الْيَقِينِ وَأَنْتُمْ مُخَالِفُونَ لَهُمَا فِي التَّغْيِيرِ وَالتَّحْرِيفِ وَالتَّعَلُّقِ بِالْأَمْرِ الْمَشُوبِ بِالتَّزْيِيفِ
It means closer in following Moses (ṣ). We agree with him in the foundations of the religion and affirm his book with clear conviction, whereas you contradict them both by altering, distorting, and depending on misconstruing the matter.
Source: Mirqāt al-Mafātīḥ 4/1426
The Prophet (ṣ) made sure to implement fasting on the day of Ashura differently than as practiced by the Jews, to make clear to everyone that Islam is a new and independent divine revelation from Allah, with its own rituals, scripture, and symbols; Islam is not a sect or extension of Judaism, Christianity, Arab idolatry, or any other religion.
The majority of scholars hold that the day of Ashura is the tenth day of Al-Muharram, although some say it is the ninth day.
Ibn Abbas reported:
أَمَرَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِصَوْمِ عَاشُورَاءَ يَوْمُ الْعَاشِرِ يعنى من الْمُحَرَّمِ
The Messenger of Allah, peace and blessings be upon him, ordered fasting on the day of Ashura, the tenth of al-Muharram.
Source: Sunan al-Tirmidhī 755, Grade: Sahih
And Al-Nawawi writes:
قَالَ أَصْحَابُنَا عَاشُورَاءُ هُوَ الْيَوْمُ الْعَاشِرُ مِنْ الْمُحَرَّمِ وَتَاسُوعَاءُ هُوَ التَّاسِعُ مِنْهُ هَذَا مَذْهَبُنَا وَبِهِ قَالَ جُمْهُورُ الْعُلَمَاءِ
Our scholars said Ashura is the tenth day of al-Muharram and Tasu’a’ is the ninth day. This is our way, as it is for the majority of scholars.
Source: al-Majmū’ Sharḥ al-Muhadhab 6/383
The Prophet (ṣ) ordered fasting on this day, by which he meant a voluntary and recommended fast, not an obligation.
Ibn Umar reported: The Prophet, peace and blessings be upon him, said:
إِنَّ عَاشُورَاءَ يَوْمٌ مِنْ أَيَّامِ اللَّهِ فَمَنْ شَاءَ صَامَهُ وَمَنْ شَاءَ تَرَكَهُ
Verily, Ashura is a day among the days of Allah. Whoever wishes to fast may do so, and whoever wishes to break his fast may do so.
Source: Ṣaḥīḥ Muslim 1126, Grade: Sahih
The reward for fasting the day of Ashura, in addition to the regular reward for fasting (already immense), is the expiation of one’s minor sins, mistakes, and imperfections throughout the previous year.
Abu Qatadah reported: The Prophet, peace and blessings be upon him, was asked about fasting the day of Ashura and he said:
يُكَفِّرُ السَّنَةَ الْمَاضِيَةَ
It will expiate the sins of the past year.
Source: Ṣaḥīḥ Muslim 1162, Grade: Sahih
It is important to appreciate that this expiation is for minor sins, which do not require specific repentance. Major sins like murder, theft, and adultery require specific repentance and in some cases legal action. One should not imagine that fasting the day of Ashura is an excuse to misbehave throughout the year.
It is the Sunnah to fast the day prior to Ashura along with it, which is the ninth of the month. Thus, one is recommended to fast both the ninth and tenth of Al-Muharram.
Ibn Abbas reported: The Messenger of Allah, peace and blessings be upon him, said:
لَئِنْ بَقِيتُ إِلَى قَابِلٍ لَأَصُومَنَّ التَّاسِعَ يعنى من الْمُحَرَّمِ
If I live until next year, I will certainly fast the ninth day of al-Muharram.
Source: Ṣaḥīḥ Muslim 1134, Grade: Sahih
Al-Hakam ibn al-A’raj reported: I went to Ibn Abbas and I said, “Tell me about fasting the day of Ashura.” Ibn Abbas said:
إِذَا رَأَيْتَ هِلاَلَ الْمُحَرَّمِ فَاعْدُدْ وَأَصْبِحْ يَوْمَ التَّاسِعِ صَائِمًا
When you see the crescent of the month of al-Muharram, count the days and wake up to fast on the ninth day.
I said, “Is this how the Messenger of Allah, peace and blessings be upon him, fasted it?” Ibn Abbas said:
Source: Ṣaḥīḥ Muslim 1133, Grade: Sahih
Al-Nawawi commented on these traditions, writing:
قَالَ الشَّافِعِيُّ وَأَصْحَابُهُ وَأَحْمَدُ وَإِسْحَاقُ وَآخَرُونَ يُسْتَحَبُّ صَوْمُ التَّاسِعِ وَالْعَاشِرِ جَمِيعًا لِأَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ صَامَ الْعَاشِرَ وَنَوَى صِيَامَ التَّاسِعِ
Al-Shafi’i and his companions, Ahmad, Ishaq, and others said it is recommended to fast the ninth and tenth of al-Muharram together, as the Prophet (ṣ) fasted the tenth and intended to fast the ninth.
Source: Sharḥ al-Nawawī ‘alá Ṣaḥīḥ Muslim 1133
And Al-Tirmidhi writes:
وَرُوِيَ عَنِ ابْنِ عَبَّاسٍ أَنَّهُ قَالَ صُومُوا التَّاسِعَ وَالْعَاشِرَ وَخَالِفُوا الْيَهُودَ وَبِهَذَا الْحَدِيثِ يَقُولُ الشَّافِعِيُّ وَأَحْمَدُ وَإِسْحَاقُ
It is reported from Ibn Abbas that he said to fast on the ninth and tenth of the month and to do so differently from the Jews, and this tradition is the same as was said by Al-Shafi’i, Ahmad, and Ishaq.
Source: Sunan al-Tirmidhī 755
Some scholars also included the eleventh day of Al-Muharram, so in their view it is recommended to fast three days on the ninth, tenth, and eleventh.
Ibn Hajar writes:
فَصِيَامُ عَاشُورَاءَ عَلَى ثَلَاثِ مَرَاتِبَ أَدْنَاهَا أَنْ يُصَامَ وَحْدَهُ وَفَوْقَهُ أَنْ يُصَامَ التَّاسِعُ مَعَهُ وَفَوْقَهُ أَنْ يُصَامَ التَّاسِعُ وَالْحَادِي عَشَرَ وَاللَّهُ أَعْلَمُ
The fast of Ashura has three levels: the lowest is to fast one day, the next is to fast the ninth day along with it, and the next is to fast the ninth, tenth, and eleventh days. Allah knows best.
Source: Fatḥ al-Bārī 1896
In any case, the most important of the days is Ashura, so if one is going to fast any day of Al-Muharram, it should be the tenth days.
May Allah empower us to sincerely fast in this blessed month of Al-Muharram and on this blessed day of Ashura.
Success comes from Allah, and Allah knows best.