Albert Barnes Commentary 1 Chronicles 27:1

"Now the children of Israel after their number, [to wit], the heads of fathers` [houses] and the captains of thousands and of hundreds, and their officers that served the king, in any matter of the courses which came in and went out month by month throughout all the months of the year-of every course were twenty and four thousand." — 1 Chronicles 27:1 (ASV)

This verse is a general heading for the list in 1 Chronicles 27:2–15. The heading has been taken from a fuller and more elaborate description of David’s army, of which the writer of Chronicles gives us only an abridgement.

Omitting the captains of thousands, the captains of hundreds, and the officers (probably “scribes”) who served the king, the author is content to record only the “chief fathers,” or heads of the divisions (1 Chronicles 28:1), and the number of Israelites in each course.