Numbers 1:18

18 And assembled them on the first day of the second month, reckoning them up by the kindreds, and houses, and families, and heads, and names of every one from twenty years old and upward,

Numbers 1:18 Meaning and Commentary

Numbers 1:18

And they assembled all the congregation together on the first
[day] of the second month
The month Ijar, as the Targum of Jonathan, answering to part of April and May: this was done on the selfsame day the Lord spake unto Moses about this affair, ( Numbers 1:1 ) ; so expeditious were he and Aaron in doing the will of God:

and they declared their pedigrees;
either Moses and Aaron, according to Aben Ezra, who inquired when they were born, because of the computation of twenty years; and then their birth was wrote down, as he says; or rather the people declared their pedigrees, of what tribe, family, and house they were, who their parents, when born, and so, of course, how old they were; Jarchi interprets it, they brought the books of their genealogies, and witnesses to confirm the birth of everyone of them, to show their genealogy according to their tribe; nor is it at all unlikely that every family and house, or master thereof, kept a register of those born to him in it, whereby their age could be ascertained as well as pedigree:

after their famines, by the house of their fathers, according to the
number of their names, from twenty years old and upwards, by their
poll:
that is, every tribe gave an account of the families in it, every family what houses were in it, and every house what number of males were in it, and of what age; and such were numbered who were twenty years old and upward.

Numbers 1:18 In-Context

16 These are the most noble princes of the multitude by their tribes and kindreds, and the chiefs of the army of Israel:

17 Whom Moses and Aaron took with all the multitude of the common people:

18 And assembled them on the first day of the second month, reckoning them up by the kindreds, and houses, and families, and heads, and names of every one from twenty years old and upward,

19 As the Lord had commanded Moses. And they were numbered in the desert of Sinai.

20 Of Ruben the eldest son of Israel, by their generations and families and houses and names of every head, all that were of the male sex, from twenty years old and upward, that were able to go forth to war,