(3) باب اقْتِنَاءِ الْكَلْبِ لِلْحَرْثِ
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."
Reference: Sahih al-Bukhari 2323
In-book reference: Book 41, Hadith 4
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 39, Hadith 516