(17) بَابُ إِذَا وَقَعَ الذُّبَابُ فِي شَرَابِ أَحَدِكُمْ فَلْيَغْمِسْهُ، فَإِنَّ فِي إِحْدَى جَنَاحَيْهِ دَاءً وَفِي الأُخْرَى شِفَاءً
Narrated Sufyan bin Abi Zuhair Ash-Shani:
That he heard Allah's Messenger (ﷺ) 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."
Reference: Sahih al-Bukhari 3325
In-book reference: Book 59, Hadith 131
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 54, Hadith 542