The king of Edom, i.e. the viceroy under Jehoshaphat, 1Ki_22:47, here called king; either because he was so called and accounted by his own people, or because that word is sometimes used for any prince or chief ruler. See Deu_33:5Jud_18:1 21:25 1Ki_20:1.
They fetched a compass, because they made a great army, which could move but slowly; and they fetched a greater compass than was usual, for some advantage which they expected by it.
There was no water; a frequent want in those hot and desert parts; and now, as it seems, increased by the extraordinary heat and dryness of the season.