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).