Ezra 6:18
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.
Numbers 3:6
Bring the tribe of Levi near, and set them before Aaron the priest, that they may minister unto him.
1 Chronicles 24:1
And the courses of the sons of Aaron were these . The sons of Aaron: Nadab and Abihu, Eleazar and Ithamar.
2 Chronicles 35:4-5
And prepare yourselves after your fathers houses by your courses, according to the writing of David king of Israel, and according to the writing of Solomon his son.
Numbers 8:9-26
And thou shalt present the Levites before the tent of meeting: and thou shalt assemble the whole congregation of the children of Israel:
1 Chronicles 23:1-26
Now David was old and full of days; and he made Solomon his son king over Israel.