The two phrases have a similar meaning. The enemy army is spoken of as if it were a flood. Alternate translation: "an army in the north will come like a flood. They will be powerful like an overflowing river" (See: [[rc://en/ta/man/translate/figs-parallelism]] and [[rc://en/ta/man/translate/figs-metaphor]])
This continues speaking of the army from the north as an overflowing river. Alternate translation: "like an overflowing river, the army from the north will destroy the land" (See: [[rc://en/ta/man/translate/figs-metaphor]])