Sahih al-Bukhari 262
صحيح البخاري#262SahihNarrated `Aisha:Whenever Allah's Messenger (ﷺ) took a bath of Janaba, he washed his hands first
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: 5:15