(34) بَاب صِيَامِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي غَيْرِ رَمَضَانَ وَاسْتِحْبَابِ أَنْ لَا يُخْلِيَ شَهْرًا عَنْ صَوْمٍ
'Abdullah b. Shaqiq reported:
I said to 'A'isha (Allah be pleased with her): Did the Messenger of Allah (ﷺ) observe fast during a month? She said, I do not know of any month in which he fasted throughout except Ramadan and (the month) in which he did not fast at all till he ran the course of his life. May peace be upon him.
Reference: Sahih Muslim 1156 b
In-book reference: Book 13, Hadith 224
USC-MSA web (English) reference(deprecated numbering scheme): Book 6, Hadith 2577