The abstract noun "captivity" can be translated as a verbal clause, and here it is probably a metaphor for Yahweh making the Ammonites prosper in a general sense. See how similar words are translated in [Jeremiah 29:14](../29/14.md). Alternate translation: "free the people of Ammon from their captivity" or "cause the people of Ammon to live well again" (See: [[rc://en/ta/man/jit/figs-abstractnouns]] and [[rc://en/ta/man/jit/figs-metaphor]])