It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that once someone asked the Holy Prophet (peace and blessings be upon him), "Which prayer is the most virtuous after the obligatory prayers?" The Holy Prophet (peace and blessings be upon him) replied, "The prayer performed in the middle part of the night." The questioner then asked, "After the fast of the month of Ramadan, which day's fast is the most virtuous?" He replied, "The month of Allah which you call Muharram (its fasts are the most virtuous)."