From the age of twenty years - Previously, the Levites did not enter upon their regular functions until the age of thirty ([Reference 1 Chro…

These were the sons of Levi after the house of their fathers. — Rather, These were the sons of Levi, according to their father…

These were the sons of Levi, after the house of their fathers ,
&c.] According to the three classes of them, as desc…

Now, because the people of Israel were so numerous, more should have been employed in the temple service, so that every Israelite who brought an of…