2-kings 14:7

He slew of Edom to the valley of salt - This war is more circumstantially related in 2 Chronicles 25:5, etc. The Idumeans had arisen in the reign of Joram king of Judah, and shaken off the yoke of the house of David. Amaziah determined to reduce them to obedience; he therefore levied an army of three hundred thousand men in his own kingdom, and hired a hundred thousand Israelites, at the price of one hundred talents. When he was about to depart at the head of this numerous army, a prophet came to him and ordered him to dismiss the Israelitish army, for God was not with them: and on the king of Judah expressing regret for the loss of his hundred talents, he was answered, that the Lord could give him much more than that. He obeyed, sent back the Israelites, and at the head of his own men attacked the Edomites in the valley of salt, slew ten thousand on the spot, and took ten thousand prisoners, all of whom he precipitated from the rock, or Selah, which was afterwards called Joktheel, a place or city supposed to be the same with Petra, which gave name to Arabia Petraea, where there must have been a great precipice, from which the place took its name of Selah or Petra.

Amaziah's Idumaean war is treated at length by the writer of Chronicles (marginal reference).

The "Valley of Salt" is usually identified with the broad open plain called the Sabkah, at the southern end of the Dead Sea - the continuation of the Ghor or Jordan gorge. At the north-western corner of this plain stands a mountain of rock-salt, and the tract between this mountain and the sea is a salt-marsh. Salt springs also abound in the plain itself, so that the name would be fully accounted for. It is doubted, however, whether the original of the word "valley," commonly used of clefts and ravines, can be applied to such a sunk plain as the Sabkah; and it is certainly most unlikely that 10,000 prisoners would have been conveyed upward of eighty miles (the distance of the Sabkah from Petra), through a rough and difficult country, only in order to be massacred. On the whole, it is perhaps most probable that the "Valley of Salt" yet remains to be discovered, and that its true position was near Selah or Petra (see Judges 1:36 note). Amaziah gave to Petra the name Joktheel, "subdued by God," in a religious spirit as an acknowledgment of the divine aid by which his victory was gained. The name failed to take permanent hold on the place, because the Edomites, on not long afterward recovering their city, restored the old appellation (2 Chronicles 28:17; compare Isaiah 16:1, and Amos 1:11).

Unto this day - The writer of Kings evidently gives the exact words of his document, composed not later than the reign of Ahaz, before whose death the Edomites had recovered Petra.

14:7 Joktheel - Which signifies, the obedience of God, that is, given him by God as a reward of his obedience to God's message by the prophet, 2 Chronicles 25:8 ,9.