By the young men of the princes of the provinces - These were probably some chosen persons out of the militia of different districts, raised by the princes of the provinces; the same as we would call lord-lieutenants of counties.
The “princes of the provinces” are the governors of districts, many of whom may have fled to the capital, as the hostile army advanced through Galilee and northern Samaria. The “young men” are their attendants, youths unaccustomed to war.
Who shall order the battle? - i. e., “Who shal join battle, begin the attack? We or the enemy?” The reply was, that the Israelites were to attack.