What does Isaiah 15:1 mean?

Isaiah begins a new oracle from the Lord, this one about the nation of Moab. This oracle, or prophecy, extends through the end of the next chapter. Some of the content parallels what is written in Jeremiah 48. The Lord may have directed both Jeremiah and Isaiah to revise an existing oracle about Moab to warn of the coming judgment of the Lord.

Israel had a long history with Moab. The Moabites were descended from Abraham's nephew Lot (Genesis 19:30–38). Moab's territory at this time extended east from the Dead Sea to the wilderness. The Moabites were most often an enemy of Israel. The two nations were in frequent conflict, from the time of the wilderness wandering (Numbers 25:1–3; 31:15–17) all the way through to Israel's King Ahab (2 Kings 3:4) and King Jehoram (2 Kings 3:5–27). Still, the two nations shared a kinship and coexisted peacefully for long seasons of their history.

The prophet's vision points forward in time, just three years from the time of his writing (Isaiah 16:14). The events that will unfold will bring about the mourning expressed in Chapter 15 and 16. Those events led to the attack and destruction of one Moabite city after another. This was apparently by an invading army from the north, like the Assyrians.

The oracle says Moab is ruined. This is because the city of Ar is destroyed in a night, as is the city of Kir. The location of Ar in Moab is unknown to modern scholars. Commentators report that Kir is likely Kir-hareseth, the capital of Moab at the time. It was east of the Dead Sea and south of the Arnon River.