Possible meanings are 1) this is a metonym for "run away without his weapons" or 2) this is meant literally as "run away wearing no clothes" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Yahweh speaks of himself by name to express the certainty of what he is declaring. See how you translated this in [Amos 2:11](./11.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]])