صَحِيحُ مُسْلِمٍ
Sahih Muslim 1163 a
The Book of Fasting
The virtue of fasting Muharram
حَدَّثَنِي قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ أَبِي بِشْرٍ، عَنْ حُمَيْدِ بْنِ عَبْدِ الرَّحْمَنِ، الْحِمْيَرِيِّ عَنْ أَبِي هُرَيْرَةَ، - رضى الله عنه - قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم أَفْضَلُ الصِّيَامِ بَعْدَ رَمَضَانَ شَهْرُ اللَّهِ الْمُحَرَّمُ وَأَفْضَلُ الصَّلاَةِ بَعْدَ الْفَرِيضَةِ صَلاَةُ اللَّيْلِ .
Abu Haraira (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying: The most excellent fast after Ramadan is God's month. al-Muharram, and the most excellent prayer after what is prescribed is prayer during the night.
Sahih Muslim, 1163 aSahihصحيح