It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) used to visit the house of an Ansari. There was another house behind theirs. This was burdensome for those people and they said, "O Messenger of Allah! You visit so-and-so's house but do not visit our house?" The Noble Prophet (peace and blessings be upon him) replied, "The reason is that there is a dog in your house." They said, "But there is a cat in those people's house as well." The Noble Prophet (peace and blessings be upon him) said, "A cat is (such) a beast (that does not prevent the angels of mercy from entering)."