'Courses' in the Bible

And David divided them into courses according to the sons of Levi: Gershon, Kohath, and Merari.

And the courses of the sons of Aaron were these . The sons of Aaron: Nadab and Abihu, Eleazar and Ithamar.

For the courses of the doorkeepers: of the Korahites, Meshelemiah the son of Kore, of the sons of Asaph.

Of these were the courses of the doorkeepers, even of the chief men, having offices like their brethren, to minister in the house of Jehovah.

These were the courses of the doorkeepers; of the sons of the Korahites, and of the sons of Merari.

Now the children of Israel after their number, to wit , the heads of fathers houses and the captains of thousands and of hundreds, and their officers that served the king, in any matter of the courses which came in and went out month by month throughout all the months of the year-of every course were twenty and four thousand.

also for the courses of the priests and the Levites, and for all the work of the service of the house of Jehovah, and for all the vessels of service in the house of Jehovah;

And, behold, there are the courses of the priests and the Levites, for all the service of the house of God: and there shall be with thee in all manner of work every willing man that hath skill, for any manner of service: also the captains and all the people will be wholly at thy commandment.