Hadith: Fasting three days of each month is fasting for a lifetime

 Bismillahirrahmanirraheem

✦ Narrated Qatadah Radi Allahu Anhu 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.

Sunan Abu Dawud, Book 13, 2443-Sahih

✦ It was narrated from Jarir bin 'Abdullah Radi Allahu Anhu that the Prophet Sallallahu Alaihi wasallam said: "Fasting three days of each month is fasting for a lifetime, and the shining days of Al-Bid, the thirteenth, fourteenth and fifteenth."

Sunan Nasaii, Book 22, 2422-Sahih

✦ It was narrated that Musa bin Talhah Radi Allahu Anhu said:

"I heard Abu Dharr, at Ar-Rabadhah, saying: 'The Messenger of Allah Sallallahu Alaihi wasallam said: if you want to fast at any time during the month then fast on the thirteenth, fourteenth and fifteenth."'

Sunan Nasaii, Book 22, Hadith 2426-Hasan