John Calvin Commentary Jeremiah 48:18

"O thou daughter that dwellest in Dibon, come down from thy glory, and sit in thirst; for the destroyer of Moab is come up against thee, he hath destroyed thy strongholds." — Jeremiah 48:18 (ASV)

Here the Prophet turns to address the city Dibon, which was renowned among those people. The mode of speaking is well known; he calls the people of the city the daughter of Dibon, and he calls the daughter an inhabitant, because the Moabites, as it has been said, always rested in safety and quietness in their own dwellings, for no one disturbed them.

It is, then, as though he had said, “You who have until now been in a quiet state, descend now from your glory, and dwell in thirst.” By thirst he means the lack of all things. Thirst is set in opposition to glory; but it is more than if the Prophet had mentioned disgrace or poverty. For there are many who are otherwise oppressed by lack, and yet find fountains or streams; but when there is no drop of water to quench thirst, it is an extreme misery.

We therefore see that the Prophet emphasizes the severity of the Moabites' punishment when he says that the citizens of Dibon would sit in thirst, because, he says, ascended against you has the waster, and the destroyer of your fortresses. We may therefore conclude that the city was fortified on all sides, so that it thought its defences sufficient to keep off enemies. But the Prophet derides this presumption, because the Chaldeans would come to pull down and destroy all these strongholds.