2 Chronicles 23:18
Also Jehoiada appointed the offices of the house of the Lord by the hand of the priests the Levites, whom David had distributed in the house of the Lord, to offer the burnt offerings of the Lord, as it is written in the law of Moses, with rejoicing and with singing, as it was ordained by David. (2 Chronicles 23:18)
Singing.
 The Pentateuch does not contain a record of the musical services to be performed in the sanctuary, and it appears that these were first established by David (see 1 Chron. 16:4-6, 37, 41, 42; 23:5; 25:1, 6, 7; 2 Chron. 29:25, 26).
Had distributed.
 David had divided the priests and Levites into various courses (1 Chron. 23:6; 24:3; 25:1).
The priests the Levites.
 The ancient versions read, “the priests and the Levites.” This construction seems required, since it was the duty of the priests to offer the burnt sacrifices (Num. 18:1-7) and of the Levitical musicians to praise the Lord with song (1 Chron. 23:5; 25:1-7).
Appointed the offices.
 This verse and the following are an expansion of the brief notice in 2 Kings 11:18: “And the priest appointed officers over the house of the Lord.” A description is here given of the restoration of the regular services of the Temple that had been seriously neglected during Athaliah’s reign (2 Chron. 24:7).