The king of Edom. — A vassal king appointed by Jehoshaphat (1 Kings 22:48).
They fetched a compass. — Went round (scil., the Dead Sea) a journey of seven days. The confederates appear to have lost their way among the mountains of Seir. They would, in any case, be greatly delayed by the cattle which it was necessary to take with them for subsistence. It is evident from the context that the distress began after the Edomite contingent had joined.
For the host, and for the cattle that followed them. — The stopping is wrong. It should be, and there was not water for the army and for the cattle which followed them. “Them,” i.e., the kings. (Comp. Judges 5:15.) “The cattle,” i.e., the herds and flocks for the maintenance of the army.
The allies appear to have marched through the deep, rocky glen of El-Ahsy (or El-Qurâhy), between Moab and Edom. They expected to find water there, as is usually the case, even in the dry season; but on this occasion the water failed.