1 Chronicles 27:1

Now the children of Israel, &c.— We have here an account of the manner in which the army was disposed. It was distributed into twelve legions, each consisting of twenty-four thousand men, who were commanded by one of the chief of the fathers, under whom there were captains of thousands and captains of hundreds. Each of these legions attended one month for the security of the king and kingdom; at the end of which they retired to their respective places of abode, and were succeeded by another legion. See Patrick and Lowman.