Numbers 1:2-5

2“Take a census of the whole Israelite community by their clans and families, listing every man by name, one by one. 3You and Aaron are to count according to their divisions all the men in Israel who are twenty years old or more and able to serve in the army. 4One man from each tribe, each of them the head of his family, is to help you. 5These are the names of the men who are to assist you: from Reuben, Elizur son of Shedeur;