Sahih al-Bukhari 5482
صحيح البخاري#5482SahihNarrated `Abdullah bin `Umar:Allah's Messenger (ﷺ) said, "If someone keeps a dog neither for guarding livestock, nor for hunting, his good deeds will decrease (in reward) by two Qirats a 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: 72:8