The word "staff" here refers to the staff a weak person leans on as he walks and is a metaphor for something that people rely on for life. Breaking this staff is a metaphor for destroying the food supply, either by destroying the crops in the fields or stopping the people from trading. Alternate translation: "When I stop you from being able to get food" or "When I make it impossible for you to get the food you depend on" (See: [[rc://en/ta/man/jit/figs-metaphor]])