en_tn/num/21/28.md

A fire blazed from Heshbon, a flame from the city of Sihon

These two phrases mean basically the same thing and emphasize that destruction will begin at Heshbon. The fire refers to a destroying army. AT: "King Sihon led a strong army from the city of Heshbon" (See: rc://en/ta/man/translate/figs-parallelism and rc://en/ta/man/translate/figs-metaphor)

devoured Ar of Moab

The army of Sihon is spoken of as if it was an animal that ate up the city of Ar. AT: "destroyed the town of Ar in the land of Moab" (See: rc://en/ta/man/translate/figs-metaphor)