Paul uses this question to get people to think about what they need to do in order not to be afraid of rulers. AT: "Let me tell you how you can be unafraid of the ruler." (See: [[rc://en/ta/man/translate/figs-rquestion]])
You can translate this in a positive form. AT: "he carries the sword for a very good reason" or "he has the power to punish people, and he will punish people" (See: [[rc://en/ta/man/translate/figs-litotes]])
Here "wrath" represents the punishment people receive when they do evil deeds. AT: "a person who punishes people as an expression of the government's anger against evil" (See: [[rc://en/ta/man/translate/figs-metonymy]])