The oracle against Moab began with a reference to its downfall being planned from Heshbon (see Jeremiah 48:2). It closes in the last few verses with a reference to Heshbon again (see Jeremiah 48:45–46). This shows that there is a deliberate structure to the oracle.1
Jeremiah once again quotes from another part of Scripture. In this case he goes all the way back to the days when Moses was leading Israel to the borders of the land in Numbers 21:1–24:25. On their journey, the Lord gave Israel victory over Sihon, king of the Ammonites. King Sihon had previously defeated the king of Moab and taken the city of Heshbon from them. Numbers 21:27–30 records a ballad that was sung at the time celebrating Sihon’s capture of Heshbon. Jeremiah quotes freely from this ballad in Jeremiah 48:45–46 and once again speaks of the fact that the current attack on Moab would come from Heshbon, also referred to here as the house of Sihon
as per the ballad (see Numbers 21:28). Just as Sihon had inflicted defeat on Moab, so now the invader from the north would destroy the forehead of Moab, the crown of the sons of tumult,
which probably refers to the northern regions of Moab. The people of Moab would have hoped to find refuge in Heshbon, but instead In the shadows of Heshbon fugitives stop without strength.
There is no refuge in the city that has become the launching pad of invasion.2
Continuing his use of the ballad in Numbers 21:1–35 Jeremiah declares the woe that is coming to Moab, “The people of Chemosh are undone, for your sons have been taken captive, and your daughters into captivity." Chemosh was the god of Moab and the defeat of Moab exposes just how ineffective their god is in protecting them. The reference to the forehead of Moab being destroyed also seems to be a quotation from Numbers 24:17 where the prophet Balaam speaks a word from the Lord against Moab in which a star shall come from Jacob, and a scepter shall rise out of Israel; it shall crush the forehead of Moab, and break down all the sons of Sheth
(Numbers 24:17). These words are about to be fulfilled.3 The invading force may come from Babylon, but it is indeed the Lord of Israel who is rising up against Moab.
45 “In the shadow of Heshbon fugitives stop without strength, for fire came out from Heshbon, flame from the house of Sihon; it has destroyed the forehead of Moab, the crown of the sons of tumult.