I asked 'A'isha (Allah be pleased with her) about the fasting of the Messenger of Allah ﷺ. She said: He used to observe fast (at times so continuously) that we said: He has fasted (never to break), and he did not observe fast till we said: He has given up perhaps never to fast, and I never saw him observing (voluntary fasts) more in any other month than that of Sha'ban. (lt appeared as if) he observed fast throughout the whole of Sha'ban except a few (days).

عَنْ صِيَامِ رَسُولِ اللَّهِ ﷺ فَقَالَتْ كَانَ يَصُومُ حَتَّى نَقُولَ قَدْ صَامَ وَيُفْطِرُ حَتَّى نَقُولَ قَدْ أَفْطَرَ وَلَمْ أَرَهُ صَائِمًا مِنْ شَهْرٍ قَطُّ أَكْثَرَ مِنْ صِيَامِهِ مِنْ شَعْبَانَ كَانَ يَصُومُ شَعْبَانَ كُلَّهُ كَانَ يَصُومُ شَعْبَانَ إِلاَّ قَلِيلاً