Sayyiduna Abu Huraira (may Allah be pleased with him) narrates in a marfu’ form that it was asked from the Prophet (peace and blessings be upon him): Which prayer is the best after the obligatory prayers? Which fast is the best after the fast of Ramadan? So the Prophet (peace and blessings be upon him) said: “After the obligatory prayer, the best prayer is a person’s prayer in the last third of the night, and after the fast of Ramadan, the best fast is the fast of Allah’s month, Muharram.”
Hadith Referenceمسند اسحاق بن راهويه / كتاب الصوم / 410
Hadith Takhrij«مسلم ، كتاب الصيام ، باب فضل صوم المحرم ، رقم : 1163 . سنن ابوداود ، كتاب الصيام ، باب فى صول المحرم ، رقم : 2429 . سنن ترمذي ، رقم : 438 . سنن ابن ماجه ، رقم : 1742 . مسند احمد : 302/2 .»
Sayyiduna Abu Hurairah (may Allah be pleased with him) narrated from the Messenger of Allah (peace and blessings be upon him), he (peace be upon him) said: "The most virtuous prayer after the obligatory prayers is the night prayer (Tahajjud), and the most virtuous fast after the fasts of Ramadan is the fast of Allah's month, Muharram."
Hadith Referenceمسند اسحاق بن راهويه / كتاب الصوم / 411