Albert Barnes Commentary 2 Chronicles 8:14

"And he appointed, according to the ordinance of David his father, the courses of the priests to their service, and the Levites to their offices, to praise, and to minister before the priests, 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 (ASV)

The man of God — This phrase, so common in Kings (see the introduction to Kings, 4th note), is rare in Chronicles, and is applied only to Moses (1 Chronicles 23:14), David, and one other prophet (2 Chronicles 25:7, 9).