Maliks Muwatta Book 54, Hadith Number 13.
Section : Concerning Dogs.
Malik related to me from Nafi from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, said, “Whoever acquires a dog other than a sheepdog or hunting dog, will have two qirats deducted from the reward of his good actions every day.”
Malik related to me from Nafi from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, ordered dogs to be killed.