Fasting in the holy month of Muharram is very virtuous and yields great reward. Consider the following hadith:

عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللهُ عَنْهُ، قَالَ: قَالَ رَسُولُ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: «أَفْضَلُ الصِّيَامِ، بَعْدَ رَمَضَانَ، شَهْرُ اللهِ الْمُحَرَّمُ، وَأَفْضَلُ الصَّلَاةِ، بَعْدَ الْفَرِيضَةِ، صَلَاةُ اللَّيْلِ»

Abu Haraira (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying: The most excellent fast after Ramadan is God's month. al-Muharram, and the most excellent prayer after what is prescribed is prayer during the night.


Additionally, one should try and fast on the 10th of Muharram which is called ‘Aashooraa’. Consider the following hadiths:

عَنْ بَعْضِ، أَزْوَاجِ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَتْ: «كَانَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ يَصُومُ تِسْعَ ذِي الْحِجَّةِ، وَيَوْمَ عَاشُورَاءَ، وَثَلَاثَةَ أَيَّامٍ مِنْ كُلِّ شَهْرٍ، أَوَّلَ اثْنَيْنِ مِنَ الشَّهْرِ وَالْخَمِيسَ»

Narrated One of the wives of the Prophet: Hunaydah ibn Khalid narrated from his wife on the authority of one of the wives of the Prophet (ﷺ) who said: The Messenger of Allah (ﷺ) used to fast the first nine days of Dhul-Hijjah, Ashura' and three days of every month, that is, the first Monday (of the month) and Thursday.

عَنِ ابْنِ عَبَّاسٍ قَالَ: لَمَّا قَدِمَ النَّبِيُّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ الْمَدِينَةَ وَجَدَ الْيَهُودَ يَصُومُونَ عَاشُورَاءَ، فَسُئِلُوا عَنْ ذَلِكَ، فَقَالُوا: هَذَا الْيَوْمُ الَّذِي أَظْهَرَ اللَّهُ فِيهِ مُوسَى عَلَى فِرْعَوْنَ وَنَحْنُ نَصُومُهُ تَعْظِيمًا لَهُ، فَقَالَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: «نَحْنُ أَوْلَى بِمُوسَى مِنْكُمْ»، وَأَمَرَ بِصِيَامِهِ

Ibn 'Abbas said: When the Prophet (ﷺ) came to Medina, he found the Jews observing fast on the day of 'Ashurah; so they were asked about it (by the Prophet). They said: This is a day on which Allah gave Moses domination over Pharaoh. We fast on it out of reverence to him. The Messenger of Allah (ﷺ) said: We have a closer connection with Moses than you have. He then gave orders that it should be observed.

عَنْ أَبِي قَتَادَةَ، أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: صِيَامُ يَوْمِ عَاشُورَاءَ، إِنِّي أَحْتَسِبُ عَلَى اللهِ أَنْ يُكَفِّرَ السَّنَةَ الَّتِي قَبْلَهُ

Abu Qatadah narrated that: the Prophet said: "Fast the Day of Ashura, for indeed I anticipate that Allah will forgive (the sins of) the year before it."



NOTE: When fasting on the day of ‘Aashooraa’ one should also fast either on the day before it or after it in order to avoid imitation of previous nations.