Albert Barnes Commentary 2 Chronicles 28:20

"And Tilgath-pilneser king of Assyria came unto him, and distressed him, but strengthened him not." — 2 Chronicles 28:20 (ASV)

Tilgath-pilneser - This form of the name is doubly corrupt. See the properly Hebraized form in 2 Kings 15:29.

Distressed him, but strengthened him not - This statement, along with the one at the end of 2 Chronicles 28:21, supplements and does not contradict the account in 2 Kings 16:9. The writer’s purpose here is to note that the material assistance Tiglath-pileser gave to Ahaz was no real “help” or “strength,” but was instead a cause of “distress.”