It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: After the obligatory prayers, the most virtuous prayer is the one performed in the middle part of the night, and after the fasts of the month of Ramadan, the most virtuous fast is that of Allah’s month which you call Muharram.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 8534
Hadith Gradingحکم دارالسلام:إسنادہ صحیح ، م : 1163