For there is a fire gone out of Heshbon, a flame from the city of Sihon: it hath consumed ar of Moab, and the lords of the high places of Arnon. (Numbers 21:28)
This refers to the conquests by Sihon of the territories surrounding Heshbon, the fire and flames being a symbol of war (see Amos 1:7, 10, 12, 14; 2:2, 5).