Because this is about future events, it can also be stated in the future tense. Alternate translation: "fire will come out of their mouth and devour their enemies"
Fire burning and killing people is spoken of as if it were an animal that could eat them up. Alternate translation: "fire will come ... and destroy their enemies" or "fire will come ... and completely burn up their enemies" (See: [[rc://en/ta/man/jit/figs-metaphor]])