Albert Barnes 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 - “Jacob” is used here to denote the kingdom of Israel, or Samaria. The word ‘glory’ here denotes dignity, power; that on which they relied, and of which they boasted.

Shall be made thin - Shall be diminished, as a body wastes away by disease, and becomes feeble. The prophet sets forth the calamities of Ephraim by two figures; the first is that of a “body” that becomes emaciated by sickness, the other that of the harvest when all the fruits are gathered except a few in the upper branches (Isaiah 17:5–6).

And the fatness his flesh shall wax lean - He shall become feeble, as a man does by wasting sickness. Chaldee, ‘The riches of his glory shall be removed.’