The people of God speaking as one person now have salvation and righteousness as their distinct appearance visible to all. "Garments" and "robe" are clothing that everyone can see. (See: [[rc://en/ta/man/translate/figs-metaphor]])
This is saying the same thing in two ways. The fact that whatever God says he will do is certainly going to happen is compared to the fact that seeds sprout after planting. AT: "Just as seeds sown in a garden sprout from the soil and grow" (See: [[rc://en/ta/man/translate/figs-parallelism]] and [[rc://en/ta/man/translate/figs-simile]])