The word "kingdom" is a metonym for the people who live in the kingdom. Alternate translation: "If the people who live in a kingdom are divided against each other" (See: [[rc://en/ta/man/jit/figs-metonymy]])
Here "stand" is a metaphor that means endure, or continue to exist. Alternate translation: "cannot endure" or "will end" (See: [[rc://en/ta/man/jit/figs-metaphor]])