FASTING CHAPTER · 68 – FAST THREE DAYS EACH MONTH
Ibn Milhan al-Kays, may Allah be pleased with him, narrated from his father:
The Messenger of Allah, peace and blessings be upon him, commanded us to fast the thirteenth, fourteenth, and fifteenth days of each month, and he said, “The fasting of these days is like fasting the entire year.”
Abdullah ibn Mas'ud, may Allah be pleased with him, narrated:
The Messenger of Allah, peace and blessings be upon him, would fast three days each month, during its bright (or full) days.