John Gill Commentary 2 Chronicles 17:18

"and next to him Jehozabad and with him a hundred and fourscore thousand ready prepared for war." — 2 Chronicles 17:18 (ASV)

And next to him, was Jehozabad
According to the Targum he encamped next him:

and with him one hundred and fourscore thousand ready prepared for war ;
being able bodied men, well disciplined, valiant, and well armed; these numbers of Judah and Benjamin put together amount to 1,160,000 men, whereas Asa only brought into the field 580,000; but it should be considered there had been a long time of peace, many had come off from the ten tribes to Judah, and the promise of multiplying the seed of Abraham was eminently fulfilled.