And the families of the priests were listed by their fathers' names, but the Levites, of twenty years old and over, were listed in relation to their work in their divisions;

These were the sons of Levi, grouped by families, the heads of the families of those who were numbered by name, by heads, all those of twenty years old and over who did the work of the house of the Lord.

So among the last acts of David was the numbering of the sons of Levi, from twenty years old and over.

Let all the children of Levi be numbered by their families and their fathers' houses; let every male of a month old and over be numbered.

And the sons of Merari by their families: Mahli and Mushi. These are the families of the Levites in the order of their fathers' houses.

All those from thirty to fifty years old who are able to do the work of the Tent of meeting.

And those of the sons of Gershon who were numbered by families,

And those of the sons of Merari who were numbered by families, in the order of their fathers' houses,

And all the Levites who were numbered by Moses and Aaron and the chiefs of the people, by families, in the order of their fathers' houses,

This is the rule for the Levites: those of twenty-five years old and over are to go in and do the work of the Tent of meeting;

Say to the children of Israel that they are to give you rods, one for every family, for every chief, the head of his father's house, making twelve rods; let every man's name be placed on his rod.

And of the rest of the sons of Levi: of the sons of Amram, Shubael; of the sons of Shubael, Jehdeiah.

Then Hezekiah put in order the divisions of the priests and Levites, every man in his division, in relation to his work, for the burned offerings and peace-offerings, and for the ordering of worship and for giving praise at the doors of the Lord's house.

And these were the people who went up from Tel-melah, Tel-harsha, Cherub, Addan, and Immer. But having no knowledge of their fathers' families or offspring, it was not certain that they were Israelites;

Treasury of Scripture Knowledge

Summary

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;

Bible References

Genealogy

Let all the children of Levi be numbered by their families and their fathers' houses; let every male of a month old and over be numbered.
And those of the sons of Gershon who were numbered by families,
Say to the children of Israel that they are to give you rods, one for every family, for every chief, the head of his father's house, making twelve rods; let every man's name be placed on his rod.
And these were the people who went up from Tel-melah, Tel-harsha, Cherub, Addan, and Immer. But having no knowledge of their fathers' families or offspring, it was not certain that they were Israelites;

Twenty

All those from thirty to fifty years old who are able to do the work of the Tent of meeting.
This is the rule for the Levites: those of twenty-five years old and over are to go in and do the work of the Tent of meeting;
These were the sons of Levi, grouped by families, the heads of the families of those who were numbered by name, by heads, all those of twenty years old and over who did the work of the house of the Lord.

By their courses

Then Hezekiah put in order the divisions of the priests and Levites, every man in his division, in relation to his work, for the burned offerings and peace-offerings, and for the ordering of worship and for giving praise at the doors of the Lord's house.
And of the rest of the sons of Levi: of the sons of Amram, Shubael; of the sons of Shubael, Jehdeiah.

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain

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