In prophecy things that will happen in the future are often referred to as if they had already happened. This emphasizes that the prophecy will certainly come true. Alternate translation: "enemies from other countries will take my people, Israel, as slaves" (See: [[rc://en/ta/man/translate/figs-pastforfuture]])
What they do not understand can be made explicit. Alternate translation: "because they do not understand Yahweh or his law" (See: [[rc://en/ta/man/translate/figs-explicit]])