24:1 The divisions of Aaron’s descendants were as follows: The sons of Aaron: Nadab, Abihu, Eleazar, and Ithamar. 

David organized the priests and Levites who would be taking care of and officiating the future temple.

24:2 Nadab and Abihu died before their father did; they had no sons. Eleazar and Ithamar served as priests. 

Nadab and Abihu were sons of Aaron. They were slain by God when they offered strange fire on the altar.

24:3 David, Zadok (a descendant of Eleazar), and Ahimelech (a descendant of Ithamar) divided them into groups to carry out their assigned responsibilities. 

Zadok and Ahimelech served with David before he became king. David divided the Levitical priests by lot. These priests would serve in the temple for two week shifts every 48 weeks.

24:4 The descendants of Eleazar had more leaders than the descendants of Ithamar, so they divided them up accordingly; the descendants of Eleazar had sixteen leaders, while the descendants of Ithamar had eight. 24:5 They divided them by lots, for there were officials of the holy place and officials designated by God among the descendants of both Eleazar and Ithamar. 24:6 The scribe Shemaiah son of Nethanel, a Levite, wrote down their names before the king, the officials, Zadok the priest, Ahimelech son of Abiathar, and the leaders of the priestly and Levite families. One family was drawn by lot from Eleazar, and then the next from Ithamar. 24:7 The first lot went to Jehoiarib, the second to Jedaiah, 24:8 the third to Harim, the fourth to Seorim, 24:9 the fifth to Malkijah, the sixth to Mijamin, 24:10 the seventh to Hakkoz, the eighth to Abijah, 24:11 the ninth to Jeshua, the tenth to Shecaniah, 24:12 the eleventh to Eliashib, the twelfth to Jakim, 24:13 the thirteenth to Huppah, the fourteenth to Jeshebeab, 24:14  the fifteenth to Bilgah, the sixteenth to Immer, 24:15 the seventeenth to Hezir, the eighteenth to Happizzez, 24:16 the nineteenth to Pethahiah, the twentieth to Jehezkel, 24:17 the twenty-first to Jakin, the twenty-second to Gamul, 24:18 the twenty-third to Delaiah, the twenty-fourth to Maaziah. 24:19 This was the order in which they carried out their assigned responsibilities when they entered the Lord’s temple, according to the regulations given them by their ancestor Aaron, just as the Lord God of Israel had instructed him. 

David divided the priests into 24 groups. Each group would work approximately two weeks per year. With 24 groups and 52 weeks, the service would rotate around the calendar. This arrangement was re-instituted after the Jewish return from Persia. This arrangement continued into New Testament times. This means that the course which was assigned to Abijah eventually descended to Zachariah, who then became the father of John the Baptist. 

24:20 The rest of the Levites included: Shubael from the sons of Amram, Jehdeiah from the sons of Shubael, 24:21 the firstborn Isshiah from Rehabiah and the sons of Rehabiah, 24:22 Shelomoth from the Izharites, Jahath from the sons of Shelomoth. 24:23 The sons of Hebron: Jeriah, Amariah the second, Jahaziel the third, and Jekameam the fourth. 24:24 The son of Uzziel: Micah; Shamir from the sons of Micah. 24:25 The brother of Micah: Isshiah. Zechariah from the sons of Isshiah. 24:26 The sons of Merari: Mahli and Mushi. The son of Jaaziah: Beno. 24:27 The sons of Merari, from Jaaziah: Beno, Shoham, Zaccur, and Ibri. 24:28 From Mahli: Eleazar, who had no sons. 24:29 From Kish: Jerahmeel. 24:30 The sons of Mushi: Mahli, Eder, and Jerimoth. These were the Levites, listed by their families. 24:31 Just like their relatives, the descendants of Aaron, they also cast lots before King David, Zadok, Ahimelech, the leaders of families, the priests, and the Levites. The families of the oldest son cast lots along with the those of the youngest. 

The genealogies of the other Levitical priests were given. By casting lots, no favoritism could be shown in the kinds of services which were performed by the different families of the Levitical priests.