Who seems to have been his father's lieutenant, because his father was captain of the king's guard, 2 Samuel 8:18, and therefore needed a deputy in the one or in the other place.
Related Commentaries of 1 Chronicles 27:6
1 Chronicles 27:6
6 This is that Benaiah, who was mighty among the thirty, and above the thirty: and in his course was Ammizabad his son.