en_tn/rom/13/04.md

he does not carry the sword for no reason

You can translate this in a positive form. Alternate translation: "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/jit/figs-litotes)

carry the sword

Roman governors carried a short sword as a symbol of their authority. (See: rc://en/ta/man/jit/figs-metonymy)

an avenger for wrath on the one who does evil

Here "wrath" represents the punishment people receive when they do evil deeds. Alternate translation: "a person who punishes, on God's behalf, those who do evil" (See: rc://en/ta/man/jit/figs-metonymy)