Abdallah b. Mughaffal reported the Prophet as saying, "Were dogs not a species of creature I should command that they all be killed; but kill every pure black one."
Abu Dawud and Darimi transmitted it. Tirmidhi and Nasa'i added, "No family attaches itself to a dog without a qirat of their good deeds being deducted daily, except in the case of a hunting dog, a farm dog, or a sheepdog.”