Divrey Hayamim Bais 8:14

14 And he appointed, according to the mishpat Dovid Aviv, the machlekot (divisions) of the Kohanim to their avodah service, and the Levi’im to their mishmerot (watches), to praise and minister before the Kohanim, as the requirement of every yom required; the Sho’arim (Gatekeepers) also by their machlekot (divisions) at every sha’ar; for thus was the mitzvot Dovid Ish HaElohim.

Divrey Hayamim Bais 8:14 Meaning and Commentary

2 Chronicles 8:14

And he appointed, according to the order of David his father,
the courses of the priests to their service
The twenty four courses which served weekly in their turns, ( 1 Chronicles 24:1-31 )

and the Levites to their charges, to praise and minister before the
priests, as duty of every day required;
who also had their courses by lot, to sing the praises of God, when the priests sacrificed, or blew the trumpets, ( 1 Chronicles 25:1-31 ) ,

the porters also by their courses at every gate;
from hence Dr. Lightfoot concludes that these were divided into twenty four classes, as the priests and Levite singers were:

for so had David the man of God commanded,
( 1 Chronicles 26:1-32 ) , who in all these affairs acted as a prophet, under the inspiration and direction of the Holy Spirit of God.

Divrey Hayamim Bais 8:14 In-Context

12 Then Sh’lomo offered up Olot unto Hashem on the Mizbe’ach Hashem, which he had built before the Ulam,

13 Even according to the requirement of each day on its day, offering according to the mitzvat Moshe, on the Shabbatot, and on Rosh Chodesh, and on the Mo’adot, three times in the year, even in the Chag HaMatzot, and in the Chag HaShavuot, and in the Chag HaSukkot.

14 And he appointed, according to the mishpat Dovid Aviv, the machlekot (divisions) of the Kohanim to their avodah service, and the Levi’im to their mishmerot (watches), to praise and minister before the Kohanim, as the requirement of every yom required; the Sho’arim (Gatekeepers) also by their machlekot (divisions) at every sha’ar; for thus was the mitzvot Dovid Ish HaElohim.

15 And they deviated not from the mitzvat HaMelech unto the Kohanim and Levi’im concerning any matter, or concerning the otzarot.

16 Now all the work of Sh’lomo was carried out from the yom musad (day of the foundation) of the Beis Hashem until its completion. So the Beis Hashem was perfected.