Answered by Shaykh Faraz Rabbani
Please tell me if we are allowed to fast the WHOLE of Muharram as is inferred by the following hadith in your recent posting on this holy month:
‘If you want to fast a month after Ramadan, then fast Muharram, for it has a day in which Allah forgave an entire people, and He turns to others in repentance.’ [Tirmidhi (841)]
Some people prohibit fasting the whole of Muharram because they say that Prophet Muhammad (SAW) didn’t wholly fast any month other than Ramadan.
Yes, it is permitted to fast the entire month. Imam Nawawi (Allah have mercy on him) discusses the implications of this, and similar hadiths in his Majmu` Sharh al-Muhadhdhab and explains that there is virtue (fadila) in fasting the entire month. [6.439-440]
This is confirmed by Imam al-Buhuti (Allah have mercy on him), the top reference for fatwa in the Hanbali school, in his Kashshaf al-Qina`, [2.338] also based on the same hadiths.
This is also mentioned explicitly in top Maliki works, such as Imam Illish’s Minah al-Jalil Sharh Mukhtasar al-Khalil [2.119] and Imam Dardir’s Sharh al-Kabir (with Imam Dasuqi’s Hashiya) [1.516]
I could not find this as being specifically recommended in the Hanafi school, though. However, there is nothing to indicate that it is disliked, either.
And Allah alone gives success.