Sahih al-Bukhari 5481
صحيح البخاري#5481SahihNarrated `Abdullah bin `Umar:I heard the Prophet (ﷺ) saying, "If someone keeps a dog neither for hunting, nor for guarding livestock, the reward (for his good deeds) will be reduced by two Qirats per day
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: 72:7