This continues the hypothetical statement from the previous verse. It describes a result that did not happen, because Yahweh was actually on their side. Alternate translation: "The water did not sweep us away ... did not drown us" (See: [[rc://en/ta/man/translate/figs-hypo]])
Here the enemies of the writer are spoken of as if they were a raging river that would have drowned the Israelites. Alternate translation: "our enemies would have destroyed us" (See: [[rc://en/ta/man/translate/figs-metaphor]])