The Messenger of Allah ﷺ used to fast three days at the beginning of every month, and he rarely missed fasting on Friday.
أخبرنا محمد بن علي بن الحسن بن شقيق قال أبي أنبأنا أبو حمزة عن عاصم عن زر
كان رسول الله ﷺ يصوم ثلاثة أيام من غرة كل شهر وقلما يفطر يوم الجمعة
Graded, its chain of transmission is hasan. Abu Dawud narrated it in the Book of Fasting, Chapter on fasting three days each month, hadith 2450, Tirmidhi in the Book of Fasting, Chapter on what has been said about fasting on Friday, hadith 742, and Ibn Majah in the Book of Fasting, Chapter on fasting on Friday, hadith 1725, from the hadith of Asim bin Abu Najud, through the same chain. Tirmidhi said, hasan gharib. It is also found in Kubra, hadith 2677.