Numbers 1:19-21

Revised Standard Version

¹⁹ as the Lord commanded Moses. So he numbered them in the wilderness of Sinai.

²⁰ The people of Reuben, Israel’s first-born, their generations, by their families, 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 forth to war: ²¹ the number of the tribe of Reuben was forty-six thousand five hundred.