Sahih Bukhari

Narrated As-Sa'ib bin Yazid:Abu Sufyan bin Abu Zuhair, a man from Azd Shanu'a and one of the companions of the Prophet (ﷺ) said, ""I heard Allah's Messenger (ﷺ) saying, 'If one keeps a dog which is meant for guarding neither a farm nor cattle, one Qirat of the reward of his good deeds is deducted daily."" I said, ""Did you hear this from Allah's Messenger (ﷺ)?"" He said, ""Yes, by the Lord of this Mosque