1 Chronicles 27:5
The third captain of the host for the third month was Benaiah the son of Jehoiada, a chief priest: and in his course were twenty and four thousand. The third captain of the host for the third month was Benaiah the son of Jehoiada, a chief priest: and in his course were twenty and four thousand.
David maintained a standing army arranged in twelve divisions that took duty in rotation, one for each month, and Benaiah son of Jehoiada held command of the third division for the third month with twenty-four thousand men under his course. The twelve courses serving month by month show the year divided into twelve months, a twelve-month year. That register of the regular army may account for the higher census total in Chronicles than in Samuel, if Chronicles counted in the regular army even when its actual strength ran a little below full number.
Benaiah son of Jehoiada was a priest, even a chief priest, under David, who served as captain of the king's guard in David's reign and afterward as captain of the host under Solomon. His priestly standing joined with command of troops, taken together with 1 Kings 4:4, shows that more than one high priest could be in service at the same time under David. His captaincy stands as one case of priests enrolled as military commanders, a thing not strange because priests came of warrior ancestry. In the view of those who pressed the point, that union of priesthood and arms proves the Levitical priesthood had grown into a strong warrior caste, for the unceasing work of dealing the death stroke to sacrificial victims with steady aim and strong arm while standing in their blood hardened priests to shed the blood of a human foe, until the work of priest and butcher had become almost identical. The same appointment illustrates that the priesthood was carried on through the descendants of a single family without regard to individual character, so that honor attached to the office or institution rather than to the men holding it, unlike prophets who were chosen for personal fitness.