en_tn_condensed/jer/48/25.md

The horn of Moab has been hacked off; its arm has been broken

Both of these statements mean the same thing. Here "horn" and "arm" represent power. To have these hacked off or broken means to lose one's power. This can be stated in active form. Alternate translation: "Moab has become weak; the people are not able to fight anymore" (See: rc://en/ta/man/jit/figs-parallelism and rc://en/ta/man/jit/figs-metonymy and rc://en/ta/man/jit/figs-activepassive)

this is Yahweh's declaration

Yahweh speaks of himself by name to express the certainty of what he is declaring. See how you translated this in Jeremiah 1:8. Alternate translation: "this is what Yahweh has declared" or "this is what I, Yahweh, have declared" (See: rc://en/ta/man/jit/figs-123person)