‏الطهارة : Hadeeth No:549 Abu Huraira reported: The Messenger of Allaah (sallAllaahu alayhi wa sallam) said: The purification of the utensil belonging to any one of you, after it is licked by a dog, lies in washing it seven times, using sand for the first time....

‏البيوع : Hadeeth No:3814 Ibn Mughaffal reported: Allaah's Messenger (sallAllaahu alayhi wa sallam) ordered the killing of dogs and then said: what is the trouble with them (the people of Medina)? How dogs are nuisance to them (the citizens of Medina)? He then permitted keehing of dogs for hunting and (the protection of) her...