“King Amaziah killed ten thousand Edomites in the Valley of Salt. He took Sela by storm. He called it Joktheel, which is its name to this day.”
King Amaziah led an expedition to Edom, where he killed over 10,000 people. He renamed Sela Joktheel, which was its name when this biblical writer was alive. Edom was southeast of Judah and had revolted against his great grandfather King Jehoram earlier in chapter 8. The Valley of the Salt is where David had defeated the Edomites also.