This is a hypothetical situation that will never happen. Yahweh says this to assure the people of Israel that they will always be a nation. Alternate translation: "These permanent things will never vanish ... and Israel's descendants will never stop from forever being a nation" (See: [[rc://en/ta/man/translate/figs-hypo]])
Yahweh speaks of himself by name to express the certainty of what he is declaring. See how you translated this in [Jeremiah 1:8](../01/08.md). Alternate translation: "this is what Yahweh has declared" or "this is what I, Yahweh, have declared" (See: [[rc://en/ta/man/translate/figs-123person]])