The Book of Fasting
22/83. Chapter:
How to Fast Three Days of Each Month, And Mentioning The Differences Reported by The Narrators In The Narration Regarding that
Sunan an-Nasai
أَخْبَرَنَا أَبُو بَكْرِ بْنُ أَبِي النَّضْرِ، قَالَ حَدَّثَنَا أَبُو إِسْحَاقَ الأَشْجَعِيُّ، - كُوفِيٌّ - عَنْ عَمْرِو بْنِ قَيْسٍ الْمُلاَئِيِّ، عَنِ الْحُرِّ بْنِ الصَّيَّاحِ، عَنْ هُنَيْدَةَ بْنِ خَالِدٍ الْخُزَاعِيِّ، عَنْ حَفْصَةَ، قَالَتْ أَرْبَعٌ لَمْ يَكُنْ يَدَعُهُنَّ النَّبِيُّ صلى الله عليه وسلم صِيَامَ عَاشُورَاءَ وَالْعَشْرَ وَثَلاَثَةَ أَيَّامٍ مِنْ كُلِّ شَهْرٍ وَرَكْعَتَيْنِ قَبْلَ الْغَدَاةِ .
It was narrated that Hafsah said: "There are four things which the Prophet never gave up: Fasting 'Ashura', (fasting during) the ten days, (fasting) three days of each month, and praying two Rak'ahs before Al-Ghadah (Fajr)."
Reference : Sunan an-Nasa'i 2416In-book reference : Book 22, Hadith 327English translation : Vol. 3, Book 22, Hadith 2418