So the Levites and all Judah did according to all things that Jehoiada the priest had commanded, and took every man his men that were to come in on the sabbath, with them that were to go out on the sabbath: for Jehoiada the priest dismissed not the courses. (2 Chronicles 23:8)
The courses of priests and Levites who had completed their duties and would normally have been dismissed were retained for the present emergency to assist those who were just beginning their duties. On these courses of priests and Levites see 1 Chron. 24, 25.