Sahih al-Bukhari 147
صحيح البخاري#147SahihNarrated `Aisha:The Prophet (ﷺ) said to his wives, "You are allowed to go out to answer the call of nature
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: 4:13