Imam Al-Nawawi’s Riyad-us-Saliheen
Chapter 306
Prohibition of Keeping a Dog except as a Watchdog or Hunting Dog

1688. Ibn `Umar (May Allah be pleased with them) said: The Messenger of Allah (sallallaahu ’alayhi wa sallam) said, “He who keeps a dog other than one for guarding the fields or herds or hunting, will lose two Qirat every day out of his rewards.”
[Al-Bukhari and Muslim].

1689. Abu Hurairah (May Allah be pleased with him) said: The Messenger of Allah (sallallaahu ’alayhi wa sallam) said, “He who keeps a dog, will lose out of his good deeds equal to one Qirat every day, except one who keeps it for guarding the fields or the herd.”
[Al-Bukhari and Muslim].

     In a narration of Muslim, the Messenger of Allah (sallallaahu ’alayhi wa sallam) is reported to have said: “He who keeps a dog for any reason other than to guard his property (lands) or his flock of sheep, his good deeds equal to two Qirat will be deducted every day.”