Numbers 1:17-24
English Standard Version
Chapter 1
17Moses and Aaron took these men who had been named, 18and on the first day of the second month, they assembled the whole congregation together, who registered themselves by clans, by fathers ' houses, according to the number of names from twenty years old and upward, head by head, 19as the Lord commanded Moses. So he listed them in the wilderness of Sinai.
20The people of Reuben, Israel 's firstborn, their generations, by their clans, by their fathers ' houses, according to the number of names, head by head, every male from twenty years old and upward, all who were able to go to war:
21those listed of the tribe of Reuben were 46,500.
