Sahih Muslim Book - 13, Hadith - 2717

حَدَّثَنَا يَحْيَى بْنُ يَحْيَى أَخْبَرَنَا يَزِيدُ بْنُ زُرَيْعٍ عَنْ سَعِيدٍ الْجُرَيْرِىِّ عَنْ عَبْدِ اللَّهِ بْنِ شَقِيقٍ قَالَ قُلْتُ لِعَائِشَةَ رضى الله عنها هَلْ كَانَ النَّبِىُّ -صلى الله عليه وسلم- يَصُومُ شَهْرًا مَعْلُومًا سِوَى رَمَضَانَ قَالَتْ وَاللَّهِ إِنْ صَامَ شَهْرًا مَعْلُومًا سِوَى رَمَضَانَ حَتَّى مَضَى لِوَجْهِهِ وَلاَ أَفْطَرَهُ حَتَّى يُصِيبَ مِنْهُ.

It was narrated that ‘Abdullah bin Shaqiq said: “I said to ‘Aishah [may Allah be pleased with her]: ‘Did the Prophet fast an entire month other than Ramadan?’ She said: ‘By Allah, he did not fast any entire month other than Ramadan, until he passed away, and he would not let any month pass without fasting some of it, until he died.’’”’