The Messenger of Allah ﷺ used to fast three days at the beginning of every month.
كان رسول الله ﷺ يصوم يعني من غرة كل شهر ثلاثة أيام.
Reported by Abu Dawud (2450) from Abu Kamil, who said, "Abu Dawud told us, Shayban told us, from Asim, from Zirr, from Abdullah," and he related it.This hadith is found in Musnad Abu Dawud Tayalisi (358), and by this route it was also reported by Ibn Khuzayma (2129), Ibn Majah (1725), and Ibn Hibban (3641), except that Ibn Khuzayma combined two hadiths together, namely, "and it would be part of his fasting on Friday." As for Ibn Majah, he mentioned only the second hadith, which is the statement of Ibn Masud, "I never saw the Messenger of Allah ﷺ break his fast on a Friday," with the same chain of transmission.Its chain is hasan due to the discussion surrounding Asim, that is, Ibn Abu Najud, for his hadith is hasan. This hadith was also reported by this route by Tirmidhi (742), Nasai (2368), and Ahmad (3860).His words, "the beginning of every month," mean its start. The word "ghurrah" refers to anything that has a beginning. And his words, "I never saw him break his fast on a Friday," mean along with Thursday, because of the prohibition that came against singling out Friday for fasting.