"I will hit you with my powerful hand." Here Yahweh speaks of punishing the people as if he were literally hitting them with his hand. Alternate translation: "I will punish you" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The word "you" refers to the people of Ammon but is also a metonym for their land and their possessions. Alternate translation: "I will allow enemies to defeat you and take you, your land, and your possessions as plunder" (See: [[rc://en/ta/man/translate/figs-metonymy]])
These phrases mean basically the same thing and emphasize that Yahweh will completely destroy the people of Ammon so that they are no longer a nation. Alternate translation: "I will completely destroy you so that you are no longer a nation" (See: [[rc://en/ta/man/translate/figs-parallelism]])