The Messenger of Allah ﷺ said, "Whoever keeps a dog, except a dog for guarding livestock, hunting, or tending crops, will have one qirat deducted from his reward each day."
قال رسول الله ﷺ: من اتخذ كلبا إلا كلب ماشية، أو صيد، أو زرع، انتقص من أجره كل يوم قيراط.
Muslim narrated it in the book of Musaqah (1575:58) from Abd bin Humayd, who said, Abdul-Razzaq narrated to us, Maamar informed us, from Zuhri, from Abu Salama, from Abu Hurairah, and he mentioned it.Zuhri said, "The statement of Abu Hurairah was mentioned to Ibn Umar, and he said, 'May Allah have mercy on Abu Hurairah, he was a man of crops.'"Its meaning is that he paid close attention to this hadith, memorized it, and mastered it, because he was the one directly concerned with the matter.