'On the Sabbath' in the Bible

This is what you are to do: a third of you, priests and Levites who are coming on duty on the Sabbath, are to be gatekeepers.

So the commanders of hundreds did everything Jehoiada the priest commanded. They each brought their men—those coming on duty on the Sabbath and those going off duty on the Sabbath—for Jehoiada the priest did not release the divisions.