Charles Ellicott Commentary Isaiah 16:8

"For the fields of Heshbon languish, [and] the vine of Sibmah; the lords of the nations have broken down the choice branches thereof, which reached even unto Jazer, which wandered into the wilderness; its shoots were spread abroad, they passed over the sea." — Isaiah 16:8 (ASV)

The fields of Heshbon languish ... — For Heshbon, see Note on Isaiah 15:4. Sibmah appears as assigned to the tribe of Reuben, in Numbers 32:38, Joshua 13:19, and in Jeremiah 48:32 as famous for its vines. Jerome (Commentary on Isaiah 5) speaks of it as about half a Roman mile from Heshbon and as one of the strongest fortresses of Moab. It has not been identified by recent travelers. The names of the chief Moabite cities are brought together by Milton with a singular rhythmical majesty in Paradise Lost, Book 1, lines 406-411.

The lords of the heathen ... — The words allow for this rendering; but another version, equally admissible grammatically, is preferred by most recent critics: Its branches smote down the lords of the nations, i.e., the wine of Sibmah was so strong that it “overcame” the princes who drank of it (Isaiah 28:1; Jeremiah 23:9). In the word for “lords” (baalim), we have a parallel to the lords of the high places of Arnon in Numbers 21:28.

They have come even to Jazer. — The pronoun may refer either to the “branches of the vine” or to the “lords of the heathen” as destroyers. Adopting the former construction, we find in these words a description of the extent of the culture of the Sibmah vine. Northward it spread to Jazer on the Gilead frontier (Numbers 32:1, 3; 1 Chronicles 26:31), which was rebuilt by the Gadites (Numbers 32:35). Eastward it spread to the wilderness; westward it crossed the Dead Sea and reappeared in the vine-clad slopes of Engedi (Song of Solomon 1:14). In Jeremiah 48:32, we have the sea of Jazer. See Note there.