Charles Ellicott Commentary 2 Chronicles 17:13

"And he had many works in the cities of Judah; and men of war, mighty men of valor, in Jerusalem." — 2 Chronicles 17:13 (ASV)

Business. More accurately, much goods, or stores; literally, work (mĕlâkâh) and then produce. The Hebrew word is used this way in Exodus 22:7 and Exodus 22:10 (referring to “His neighbour’s goods”). Stores of provisions and war material seem to be intended. (Compare to 2 Chronicles 11:11.)

And the man of war ... were in Jerusalem. Or rather, and (he had) men of war ... in Jerusalem.

In Jerusalem.: Not the entire army corps whose numbers are given in 2 Chronicles 17:14–18, but simply their chiefs.