It is narrated from al-Nu'man bin Sa'd (may Allah have mercy on him) that a man came to Sayyiduna Ali (may Allah be pleased with him) and said: "O Commander of the Believers, tell me of a month in which I may fast after Ramadan." Sayyiduna Ali (may Allah be pleased with him) said: "You have asked me about something I have never heard anyone ask about except one man, whom I heard asking the Messenger of Allah (peace and blessings be upon him) this very question, and he (peace and blessings be upon him) said to him: 'If you wish to fast a month after Ramadan, then fast Muharram, for it is the month of Allah. In it there is a day on which Allah Almighty accepted the repentance of a people, and on that same day He will accept the repentance of others as well.'"
Hadith Referenceمسند أبي يعلى الموصلي / مسند علي بن أبي طالب رضي الله عنه / 426
Hadith Gradingمحدثین:إسناده ضعيف
Hadith Takhrij«حکم الحدیث مسند ابی یعلی محققاً تنسیق حسين سليم أسد - مکتبہ شاملہ :قال حسين سليم أسد: إسناده ضعيف . » «قال سعيد بن محمد السناري: ضعيف: مضى تخريجه [برقم/ 267]» «أخرجه سنن الترمذي برقم: 741، وأخرجه مسند أحمد برقم: 1337، وأخرجه سنن الدارمي برقم: 1756، وأخرجه مصنف ابن أبي شيبة برقم: 1، مسند ابویعلیٰ ترقیم الاثری: 421»