All these were (c) joined together in the vale of Siddim, which is the (d) salt sea.
(c) Ambition is the chief cause of wars among princes.
(d) Called also the dead sea, or the lake Asphaltite, near Sodom and Gomorrah.

All these were joined together in the vale of Siddim,.... Or "of fields", or "ploughed lands" (b), a fruitful vale abounding with corn; or of gardens or paradises, as the Targums of Jonathan and Jerusalem, being full of gardens and orchards, and was as the garden of the Lord, even as Eden, see Genesis 13:10; though Aben Ezra thinks it had its name from the slime or bitumen, of which there was great plenty in it, see Genesis 14:10. Now the above five kings, as they all dwelt in the plain, they entered into a confederacy, met together, and joined their forces in this vale, to oppose the four kings that were come to make war with them, as being an advantageous place, as they judged, perhaps on more accounts than one; and here they stayed to receive the enemy, and give him battle, see Genesis 14:8,
which is the salt sea; afterwards so called, not at this time, for then it would not have been fit for armies to be drawn up in battle array in it; but it was so called in the times of Moses, and after this fine vale was turned into a bituminous lake, and had its name from the saltness of the waters of the lake, or from the city Melach, or city of salt, which was near it, Joshua 15:62.
(b) "valle amaenissimorum agrorum", Munster; "in planitie agrorum", Fagius; so Jarchi; "in valle occationum", Hiller. Onomastic. Sacr. p. 937. "dicta ab agris occatis", Schmidt.

"All these (five kings) allied themselves together, (and came with their forces) into the vale of Siddim (השׂדּים, prob. fields of plains), which is the Salt Sea;" that is to say, which was changed into the Salt Sea on the destruction of its cities (Genesis 19:24-25). That there should be five kings in the five cities (πεντάπολις, Wis. 10:6) of this valley, was quite in harmony with the condition of Canaan, where even at a later period every city had its king.