The prophet compares the nations to a drop of water and to dust in order to emphasize how small and insignificant they are to Yahweh. (See: [[rc://en/ta/man/translate/figs-simile]])
This can be stated in active form. Alternate translation: "Yahweh regards them as dust on the scales" (See: [[rc://en/ta/man/translate/figs-activepassive]])