Sahih al-Bukhari 5482
Sahih al-Bukhari · Book 72: Hunting, Slaughtering · A (pet) dog
Narrated `Abdullah bin `Umar:
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ ، أَخْبَرَنَا مَالِكٌ ، عَنْ نَافِعٍ ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنِ اقْتَنَى كَلْبًا إِلاَّ كَلْبَ مَاشِيَةٍ أَوْ ضَارٍ، نَقَصَ مِنْ عَمَلِهِ كُلَّ يَوْمٍ قِيرَاطَانِ " .
Allah's Messenger (ﷺ) said, "If someone keeps a dog neither for guarding livestock, nor for hunting, his good deeds will decrease (in reward) by two Qirats a day.'