"The Messenger of Allah used to enjoin fasting three days: The first Thursday, and Monday and Monday."
Sunan an-Nasa'i Book 22, Hadith 330
← Previous Hadith "The Prophet used to fast the ten (days), and three days of each month: Monday and Thursday."

Sunan an-Nasa'i Book 22, Hadith 329 Next Hadith → "Fasting three days of each month is fasting for a lifetime, and the shining days of Al-Bid, the thirteenth, fourteenth and fifteenth."

Sunan an-Nasa'i Book 22, Hadith 331