1 Chronicles 23:28

For their duty was to wait on the sons of Aaron for the service of Yahweh’s house—in the courts, in the rooms, and in the purifying of all holy things, even the work of the service of God’s house;

Because their office was to wait on the sons of Aaron for the service of the house of the LORD, in the courts, and in the chambers, and in the purifying of all holy things, and the work of the service of the house of God;