Numbers 1:18-20

New Catholic Bible

¹⁸ and on the first day of the second month they gathered together the entire community who registered themselves by families, by the name of their fathers’ households. The men twenty years and older were listed according to their names, one by one, ¹⁹ as the Lord had commanded Moses. And so he counted them in the Sinai Desert.

²⁰ The Count of the Twelve Tribes. Thus the members of the tribe of Reuben, the oldest son of Israel, who were twenty years or older and who were fit to bear arms were listed by name according to their clans and families, one by one.