2 Chronicles 8:14

14 He appointed, according to the ordinance of David his father, the courses of the Kohanim to their service, and the Levites to their offices, to praise, and to minister before the Kohanim, as the duty of every day required; the doorkeepers also by their courses at every gate: for so had David the man of God commanded.

2 Chronicles 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.

2 Chronicles 8:14 In-Context

12 Then Shlomo offered burnt-offerings to the LORD on the altar of the LORD, which he had built before the porch,

13 even as the duty of every day required, offering according to the mitzvah of Moshe, on the Shabbatot, and on the new moons, and on the set feasts, three times in the year, [even] in the feast of matzah, and in the feast of weeks, and in the feast of booths.

14 He appointed, according to the ordinance of David his father, the courses of the Kohanim to their service, and the Levites to their offices, to praise, and to minister before the Kohanim, as the duty of every day required; the doorkeepers also by their courses at every gate: for so had David the man of God commanded.

15 They didn't depart from the mitzvah of the king to the Kohanim and Levites concerning any matter, or concerning the treasures.

16 Now all the work of Shlomo was prepared to the day of the foundation of the house of the LORD, and until it was finished. [So] the house of the LORD was completed.