Numbers 1:17-19

American Standard Version

¹⁷ And Moses and Aaron took these men that are mentioned by name: ¹⁸ and they assembled all the congregation together on the first day of the second month; and they declared their pedigrees after their families, by their fathers’ houses, according to the number of the names, from twenty years old and upward, by their polls. ¹⁹ As Jehovah commanded Moses, so he numbered them in the wilderness of Sinai.