John Gill Commentary 2 Kings 3:9

"So the king of Israel went, and the king of Judah, and the king of Edom; and they made a circuit of seven days` journey: and there was no water for the host, nor for the beasts that followed them." — 2 Kings 3:9 (ASV)

So the king of Israel went, and the king of Judah
The way of the wilderness of Edom, proposed by the latter:

and the king of Edom ;
whom they took with them in their way, who was not properly a king, but a viceroy or deputy, see (1 Kings 22:47)

and they fetched a compass of seven days journey ;
they went round the Dead Sea, and through the wilderness of Edom, and so to the borders of Moab:

and there was no water for the host, and for the cattle that followed
them ;
neither for the soldiers in the army, nor the cattle that drew the carriages, being in a wilderness.