Sahih al-Bukhari 2151
صحيح البخاري#2151SahihNarrated Abu Huraira:Allah's Messenger (ﷺ) said, "Whoever buys a sheep which has been kept unmilked for a long period, and milks it, can keep it if he is satisfied, and if he is not satisfied, he can return it, but he should pay one Sa of dates for the milk
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: 34:103