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.
And they appointed priests in their orders, etc. The order demanded devotion, so that after the Lord’s house was built and dedicated, priests and Levites who would minister in it were immediately ordained; lest the house shine in vain if those who serve God within were lacking. This should be frequently impressed upon those who, constructing monasteries with magnificent work, do not at all place teachers in them who would encourage God’s people to the works of God, but rather serve their own pleasures and desires there. But what he says about priests in their orders and Levites in their turns being appointed signifies the shifts of weeks; in which the whole assembly of each rank was distributed into twenty-four parts, so that each order would minister its turn during its week, specifically from Sabbath to Sabbath in the temple; and then, for twenty-three weeks, free from the temple's duties, they would take care of their own household affairs, as the Words of the Days narrate. For around the inner sanctuary, they had already made the porches of the temple, at the gates of which the Levites kept watch in turns, as it is also written there. But what is said, “As it is written in the book of Moses,” does not refer to the shifts of the Levites, but to the works of God; for Moses wrote what the priests and Levites ought to do in the house of God; but the shifts of the Levites and the orders of the priests into twenty-four lots, as we mentioned, were described not by Moses, but by King David with the prophets, priests, and Levites of that time. And now too, with Christ's Church being built and dedicated through the regeneration of new peoples to the faith, it is fitting to appoint priests and Levites in their orders and turns over the works of God; and the people are initiated not only into the sacraments of faith but are also instructed to perform the works of God by the examples and teachings of the righteous ones preceding in Christ; and this not by the capture of human ingenuity, but as it is written in the book of Moses. To which the Lord’s saying agrees: “Go therefore and teach all nations, baptizing them in the name of the Father and the Son and the Holy Spirit, teaching them to observe all things whatsoever I have commanded you” (Matt. 28). Therefore, we must teach our hearers not our own precepts, but those which are the commands of the law and the Gospel, if we care to reach the rewards which the Lord promised, together with those same hearers.
[AD 735] Bede on Ezra 6:18