(83) باب كَيْفَ يَصُومُ ثَلاَثَةَ أَيَّامٍ مِنْ كُلِّ شَهْرٍ وَذِكْرِ اخْتِلاَفِ النَّاقِلِينَ لِلْخَبَرِ فِي ذَلِكَ .
It was narrated that Umm Salamah said:
"The Messenger of Allah used to enjoin fasting three days: The first Thursday, and Monday and Monday." (ES)
Reference (ES): Sunan an-Nasa'i 2419 (ES)
In-book reference (ES): Book 22, Hadith 330 (ES)
English translation (ES): Vol. 3, Book 22, Hadith 2421 (ES)