Números 1:18

18 and they called the whole community together on the first day of the second month. The people registered their ancestry by their clans and families, and the men twenty years old or more were listed by name, one by one,

18 And they got together all the people on the first day of the second month; and everyone made clear his family and his father's house, by the number of the names, from twenty years old and over.