'Courses' in the Bible
They fought from heaven; the stars in their courses fought against Sisera.
And he sent them to Lebanon, ten thousand a month by courses: a month they were in Lebanon, and two months at home: and Adoniram was over the levy.
And David divided them into courses among the sons of Levi, namely, Gershon, Kohath, and Merari.
Now the children of Israel after their number, to wit, the chief fathers and captains of thousands and 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 the LORD, and for all the vessels of service in the house of the LORD.
And, behold, the courses of the priests and the Levites, even they shall be with thee for all the service of the house of God: and there shall be with thee for all manner of workmanship every willing skilful man, for any manner of service: also the princes and all the people will be wholly at thy commandment.
And he appointed, according to the order of David his father, the courses of the priests to their service, and the Levites to their charges, to praise and minister before the priests, as the duty of every day required: the porters also by their courses at every gate: for so had David the man of God commanded.
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.
And Hezekiah appointed the courses of the priests and the Levites after their courses, every man according to his service, the priests and Levites for burnt offerings and for peace offerings, to minister, and to give thanks, and to praise in the gates of the tents of the LORD.
And next him were Eden, and Miniamin, and Jeshua, and Shemaiah, Amariah, and Shecaniah, in the cities of the priests, in their set office, to give to their brethren by courses, as well to the great as to the small:
Beside their genealogy of males, from three years old and upward, even unto every one that entereth into the house of the LORD, his daily portion for their service in their charges according to their courses;
Both to the genealogy of the priests by the house of their fathers, and the Levites from twenty years old and upward, in their charges by their courses;
And prepare yourselves by the houses of your fathers, after your courses, according to the writing of David king of Israel, and according to the writing of Solomon his son.
So the service was prepared, and the priests stood in their place, and the Levites in their courses, according to the king's commandment.
And they set the priests in their divisions, and the Levites in their courses, for the service of God, which is at Jerusalem; as it is written in the book of Moses.