Sahih Muslim , Book 10, Hadith 3827 (USC-MSA) ⓘ
Abu Huraira (Allah be pleased with him) reported Allah's Messenger as saying: He who kept a dog, but not meant for hunting or watching the herd, would lose one qirat of reward every day.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، - يَعْنِي ابْنَ زِيَادٍ - عَنْ إِسْمَاعِيلَ، بْنِ سُمَيْعٍ حَدَّثَنَا أَبُو رَزِينٍ، قَالَ سَمِعْتُ أَبَا هُرَيْرَةَ، يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنِ اتَّخَذَ كَلْبًا لَيْسَ بِكَلْبِ صَيْدٍ وَلاَ غَنَمٍ نَقَصَ مِنْ عَمَلِهِ كُلَّ يَوْمٍ قِيرَاطٌ " .
also referenced under: Book 22, Hadith 74 (In-Book) & Hadith 1575 (Reference)