Authentic
Muttafaq ‘alayh (Bukhari and Muslim) Sahih al-Bukhari 2323
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…
مَنِ اقْتَنَى كَلْبًا لاَ يُغْنِي عَنْهُ زَرْعًا وَلاَ ضَرْعًا، نَقَصَ كُلَّ يَوْمٍ مِنْ عَمَلِهِ قِيرَاطٌ "