Charles Ellicott Commentary Isaiah 17:4

"And it shall come to pass in that day, that the glory of Jacob shall be made thin, and the fatness of his flesh shall wax lean." — Isaiah 17:4 (ASV)

The glory of Jacob shall be made thin. —The word is the same as that rendered “impoverished” in Judges 6:8. “Jacob” commonly stands in the prophets, like Israel, for the northern kingdom, and the words therefore point to the downfall, or, adopting the prophet’s figurative language, the emaciation, of that kingdom.