John Gill Commentary 2 Chronicles 17:14

"And this was the numbering of them according to their fathers` houses: Of Judah, the captains of thousands: Adnah the captain, and with him mighty men of valor three hundred thousand;" — 2 Chronicles 17:14 (ASV)

And these are the numbers of them, according to the house of their fathers Both of the tribe of Judah and of Benjamin: and first of Judah, the captains of thousands; some had 1000 men under them, and some one hundred: Adnah the chief; he was the principal commander or general of them: and with him mighty men of valour, three hundred thousand; such a number was under his command.