1. Chronik 24:4

And there were more chief men found of the sons of Eleazar than of the sons of Ithamar,.... Or heads of men, heads of their fathers' houses and families: and thus were they divided; among the sons of Eleazar there were sixteen chief men of the house of their fathers, and eight among the sons of Ithamar, according to the house of their fathers; in all twenty four, and into so many classes or courses did David divide them; Jarchi says at first when the tabernacle was at Shiloh, there were but sixteen courses, eight from Eleazar, and eight from Ithamar, as is explained in the treatise of fasting (n); but when David saw that there were more heads of men, or chief men of Eleazar's, he divided the courses of Eleazar into two parts, and fixed sixteen courses; and the courses of Ithamar he established as at first, eight courses; left them as they were, which he thinks appears from Ch1 24:6 but of the former number of courses, and when and by whom fixed, the Jews are divided (o); See Gill on Luk 1:5. Perhaps there were none before David's time. (n) T. Bab. Taanith, fol. 27. 1. (o) T. Bab. Taanith, fol. 27. 1.

This chapter gives us a more particular account of the distribution of the priests and Levites into their respective classes, for the more regular discharge of the duties of their offices, according to their families. I. Of the priests (v. 1-19). II. Of the Levites (Ch1 24:20-31).