(82) باب ذِكْرِ الاِخْتِلاَفِ عَلَى أَبِي عُثْمَانَ فِي حَدِيثِ أَبِي هُرَيْرَةَ فِي صِيَامِ ثَلاَثَةِ أَيَّامٍ مِنَ كُلِّ شَهْرٍ
It was narrated that Abu Dharr said:
"The Messenger of Allah said: 'Whoever fasts for three days of each month, he has fasted for a whole lifetime.' Then he said: Allah has spoken the truth in His book: Whoever brings a good deed shall have ten times the like thereof to his credit.
Reference: Sunan an-Nasa'i 2409
In-book reference: Book 22, Hadith 320
English translation: Vol. 3, Book 22, Hadith 2411