(69) باب فِي صَوْمِ الثَّلاَثِ مِنْ كُلِّ شَهْرٍ
Narrated Qatadah Ibn Malhan al-Qaysi:
The Messenger of Allah (ﷺ) used to command us to fast the days of the white (nights): thirteenth, fourteenth and fifteenth of the month. He said: This is like keeping perpetual fast.
Reference: Sunan Abi Dawud 2449
In-book reference: Book 14, Hadith 137
English translation: Book 13, Hadith 2443