John Gill Commentary 2 Kings 14:27

"And Jehovah said not that he would blot out the name of Israel from under heaven; but he saved them by the hand of Jeroboam the son of Joash." — 2 Kings 14:27 (ASV)

And the Lord said not that he would blot out the name of
Israel from under heaven
He had not yet declared it by any of his prophets that he would do so, as he afterwards did by Hosea (Hosea 1:4Hosea 1:9), and it was fulfilled in the reign of Hoshea king of Israel (2 Kings 17:1).

but he saved them by the hand of Jeroboam the son of Joash
the instrument of their deliverance from the hands of their enemies, and of recovering their borders as before.