(17) بَابُ إِذَا وَقَعَ الذُّبَابُ فِي شَرَابِ أَحَدِكُمْ فَلْيَغْمِسْهُ، فَإِنَّ فِي إِحْدَى جَنَاحَيْهِ دَاءً وَفِي الأُخْرَى شِفَاءً
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "If somebody keeps a dog, he loses one Qirat (of the reward) of his good deeds everyday, except if he keeps it for the purpose of agriculture or for the protection of livestock. "
Reference: Sahih al-Bukhari 3324
In-book reference: Book 59, Hadith 130
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 54, Hadith 541