Charles Ellicott Commentary Isaiah 65:9

"And I will bring forth a seed out of Jacob, and out of Judah an inheritor of my mountains; and my chosen shall inherit it, and my servants shall dwell there." — Isaiah 65:9 (ASV)

I will bring forth a seed out of Jacob ... —Jacob (i.e., Israel) and Judah are used to represent respectively the remnants of the two kingdoms that had been carried into captivity.

My mountains. —One of Isaiah’s characteristic phrases (Isaiah 29:11; Ezekiel 6:2–3). Not Zion only, but every hill in Canaan was a sharer in a derived sanctity.