Either during the siege, or on breaking up from before Jeruasalem, Rezin made an expedition to the lied Sea coast, and became master of the city which had belonged to Judaea about 70 years (marginal reference). Most moderns render this verse, “Rezin recovered (or restored) Elath to Edom ... and the Edomites came to Elath.” On the resemblance of the words Aram and Edom in the original, see 2 Samuel 8:12 note.
Related Commentaries of 2 Kings 16:6
2 Kings 16:6
6 At that time Rezin king of Syria recovered Elath to Syria, and drave the Jews from Elath:a and the Syrians came to Elath, and dwelt there unto this day.