An uproar is a very loud noise. Alternate translation: "The sound of many people, that is very loud like the seas" (See: [[rc://en/ta/man/translate/figs-simile]])
The enemy armies appear to be a powerful force that no one can stop. Alternate translation: "the nations come rushing in like the mighty waters" (See: [[rc://en/ta/man/translate/figs-simile]])
The word "nations" refers to the armies of those nations. Alternate translation: "the rushing of the enemy armies" (See: [[rc://en/ta/man/translate/figs-synecdoche]])