John Gill Commentary 2 Kings 3:6

"And king Jehoram went out of Samaria at that time, and mustered all Israel." — 2 Kings 3:6 (ASV)

And King Jehoram went out of Samaria the same time ,
&e.] As soon as he came to the throne:

and numbered all Israel ;
who were fit to bear arms, got them together at some certain place, and mustered them, and prepared for a war with Moab, to reduce them.