Hadith 2058

‘Abdallah b. Mas'ud said that God’s messenger used to fast the first three days every month, and he would seldom break his fast on a Friday. Tirmidhi and Nasa’i transmitted it, and Abu Dawud transmitted up to “three days every month.”

وَعَنْ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَصُومُ مِنْ غُرَّةِ كُلِّ شَهْرٍ ثَلَاثَةَ أَيَّامٍ وَقَلَّمَا كَانَ يفْطر يَوْم الْجُمُعَةَ. رَوَاهُ التِّرْمِذِيُّ وَالنَّسَائِيُّ وَرَوَاهُ أَبُو دَاوُدَ إِلَى ثَلَاثَة أَيَّام

Reference: 5620580
In-book reference: Book 7, Hadith 2058