Sahih al-Bukhari 5619
صحيح البخاري#5619SahihNarrated Anas bin Malik:Milk mixed with water was brought to Allah's Messenger (ﷺ) while a bedouin was on his right and Abu Bakr was on his left. He drank (of it) and then gave (it) to the bedouin and said, 'The right" "The right (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: 74:45