Isaiah 16:9
Therefore I will bewail with the weeping of Jazer the vine of Sibmah: I will water thee with my tears, O Heshbon, and Elealeh: for the shouting for thy summer fruits and for thy harvest is fallen. Therefore I will bewail with the weeping of Jazer the vine of Sibmah: I will water thee with my tears, O Heshbon, and Elealeh: for the shouting for thy summer fruits and for thy harvest is fallen.
Isaiah 16:9 stands in the first part of Isaiah, chapters 1 to 39. That first part is made up of single distinct prophecies published at different times and on different occasions during Isaiah's active public work as God's messenger to the rulers and the people. It does not belong to the second part, chapters 40 to 66, written in his later years and occupied wholly with the future, with deliverance from Babylonian captivity and deliverance from sin and error through the Messiah.
Within that first part it belongs to the series of prophecies about the nations in chapters 13 to 23, which includes a burden and prophecy and predictions concerning Moab. Moab was one of the oppressors of Judah.