John Gill Commentary 2 Kings 21:14

"And I will cast off the remnant of mine inheritance, and deliver them into the hand of their enemies; and they shall become a prey and a spoil to all their enemies;" — 2 Kings 21:14 (ASV)

And I will forsake the remnant of my inheritance
The whole land of Canaan was the Lord's inheritance; ten tribes in it were already removed, only Judah with Benjamin was left, and the Lord threatens to forsake that remnant:

and deliver them into the hands of their enemies, and they shall become
a prey and spoil to all their enemies ;
which was fulfilled in their captivity in Babylon.