Lincoln’s statement “a house divided against itself cannot stand” was an allusion to what?

Since Lincoln was a president during times of slavery, the north and south part of America were at ends with each other because one supported slavery and the other didn't, since a house divided against itself cannot stand I would assume he was talking about the United states and how the country couldn't stand when it was divided

Dogs have been considered man’s best friend for decades! most likely because of their kind and loyal nature. they make splendid companions. their loyalty is beyond compare and after all, a dog is the only thing on earth that loves you more than he loves himself! dogs see us as their friends and leaders, they’ll do anything in their power to ensure your comfort and safety.