Hadith 3962
عَنْ عَبْدِ اللَّهِ (يَعْنِي ابْنَ مَسْعُودٍ) رَضِيَ اللَّهُ عَنْهُ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَصُومُ ثَلَاثَةَ أَيَّامٍ مِنْ غُرَّةِ كُلِّ هِلَالٍ، وَقَلَّمَا كَانَ يُفْطِرُ يَوْمَ الْجُمُعَةِ
Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) used to fast during the first three days of every month, and he (peace and blessings be upon him) would rarely break his fast on Fridays.