Sahih al-Bukhari 143
صحيح البخاري#143SahihNarrated Ibn `Abbas:Once the Prophet (ﷺ) entered a lavatory and I placed water for his ablution. He asked, "Who placed it?" He was informed accordingly and so he said, "O Allah! Make him (Ibn `Abbas) a learned scholar in religion (Islam)
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: 4:9