حَدَّثَنَا مُحَمَّدُ بْنُ سَعِيدٍ ، حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ إِسْحَاق ، عَنْ النُّعْمَانِ بْنِ سَعْدٍ ، قَالَ : جَاءَ رَجُلٌ إِلَى عَلِيٍّ فَسَأَلَهُ عَنْ شَهْرٍ بَعْدَ شَهْرِ رَمَضَانَ يَصُومُهُ، فَقَالَ لَهُ عَلِيٌّ : مَا سَأَلَنِي أَحَدٌ عَنْ هَذَا بَعْدَ إِذْ سَمِعْتُ رَجُلًا سَأَلَ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : أَيُّ شَهْرٍ يَصُومُهُ مِنْ السَّنَةِ بَعْدَ شَهْرِ رَمَضَانَ.فَأَمَرَهُ بِصِيَامِ الْمُحَرَّمِ، وَقَالَ : " إِنَّ فِيهِ يَوْمًا تَابَ اللَّهُ عَلَى قَوْمٍ وَيَتُوبُ فِيهِ عَلَى قَوْمٍ "

Muhammad bin Saeed narrated to us, Muhammad bin Fudayl narrated to us, on the authority of Abd al-Rahman bin Ishaq, on the authority of al-Nu’man bin Sa’d, who said: A man came to Ali asked him about the month after the month of Ramadan that he fasts, and Ali said to him: No one has asked me about this after I heard a man ask the Prophet, may God bless him and grant him peace. May God bless him and grant him peace: Which month of the year should he fast after the month of Ramadan? So he commanded him to fast Muharram, and said: “Indeed, therein is a day in which God repents to A people, and therein a people will repent.”