What does 2 Chronicles 23:8 mean?

The Levites and all the people did exactly what Jehoiada the priest ordered. Each man took his group—those coming on duty and those going off duty that Sabbath—because Jehoiada hadn't let any of the divisions leave. 2 Chronicles 23:8 - Modern Text Bible

(Everyone follows Jehoiada's plan to the letter. Even those who were supposed to go off duty stay, so there's extra security.)