Angels do not enter a house with a dog or an image inside it

The Prophet (may Allah's peace and blessings be upon him) informed that the angels of mercy do not enter a house wherein is a dog or an image of animate beings. This is because images of animate beings constitute a grave sin, imitation of Allah's creation, a means leading to Shirk. And some of them depict things worshipped apart from Allah.

As for why they do not exist in a house that has a dog, it is because it eats a lot of impure things and some dogs are called devils, and angels are against the devils. It is also because of the bad smell of dogs; angels dislike bad smells.

Another reason is that it is prohibited to acquire dogs, and so he who does that is punished by being deprived of the angels of mercy entering his house, praying in it, seeking Allah's forgiveness for him, blessing him and his house, and averting the harm of the devil from him.