Volume 7 · Book 67 · Hadith 391
Narrated 'Abdullah bin 'Umar: Allah's Apostle 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.'
— Sahih Bukhari, Volume 7, Book 67: Hunting, Slaughtering, Hadith #391