Volume 4 · Book 54 · Hadith 542
Narrated Sufyan bin Abi Zuhair Ash-Shani: That he heard Allah's Apostle saying, "If somebody keeps a dog that is neither used for farm work nor for guarding the livestock, he will lose one Qirat (of the reward) of his good deeds everyday."
— Sahih Bukhari, Volume 4, Book 54: Beginning of Creation, Hadith #542