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.