Jamieson, Fausset and Brown on 2 Kings 14:7

7. He slew of Edom in the valley of salt ten thousand--In the reign of Joram the Edomites had revolted (see 2Ki 8:20). But Amaziah, determined to reduce them to their former subjection, formed a hostile expedition against them, in which he routed their army and made himself master of their capital.

the valley of salt--that part of the Ghor which comprises the salt and sandy plain to the south of the Dead Sea.

Selah--literally, "the rock"; generally thought to be Petra.

Joktheel--that is, "given" or "conquered by God." See the history of this conquest more fully detailed (2Ch 25:6-16).

2Ki 14:8-16. Joash Defeats Him.