Abu Huraira reported God’s messenger as saying, “The most excellent fast after Ramadan is in God’s month al-Muharram, and the most excellent prayer after what is prescribed is prayer during the night." Muslim transmitted it.
Hadith Referenceمشكوة المصابيح / كتاب الصوم / 2039
Hadith Gradingالألبانی:صَحِيحٌ | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه مسلم (202 / 1163)»