The Prophet, peace be upon him
, said: "Whoever keeps a dog, his good deeds will decrease every day by one
qeeraat (a unit of measurement), unless it is a dog for farming or herding." In another report, it is said: "... unless it is a dog for herding sheep, farming or hunting." (Reported by al-Bukhaari)
The Prophet, peace be upon him, said: "Angels do not enter a house wherein there is a dog or an animate picture." (Reported by Bukhari)
Many Muslims base the prohibition against keeping a dog in one's home, except for the case of working or service dogs, on these traditions.