Charles Ellicott Commentary Isaiah 15:7

"Therefore the abundance they have gotten, and that which they have laid up, shall they carry away over the brook of the willows." — Isaiah 15:7 (ASV)

Therefore the abundance ... —The picture of the flight is completed. The fugitives carry with them all the household goods they can gather, and bear them in their flight.

To the brook of the willows. —This has been variously translated. Some versions are:

1. “the torrent of the poplars”;
2. “the Arabians”; or
3. “of the wilderness.”

It was probably the Wady el Achsar, where a stream falls into the Dead Sea, between the territory of Moab and Edom, the brook Zered of Numbers 21:12, Deuteronomy 2:13. It is obviously named here as the point where the fugitives pass the boundary of their own lands. With less probability, it has been taken as a poetical equivalent for the Euphrates (Psalms 137:2).