Sahih al-Bukhari 1969
صحيح البخاري#1969SahihNarrated `Aisha:Allah's Messenger (ﷺ) used to fast till one would say that he would never stop fasting, and he would abandon fasting till one would say that he would never fast. I never saw Allah's Messenger (ﷺ) fasting for a whole month except the month of Ramadan, and did not see him fasting in any month more than in the month of Sha'ban
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 30:76