Numbers 1:3-7

from twenty years old and upward, whoever is able to go to war in Israel. You and Aaron shall count them by their armies.

With you, moreover, there shall be a man of each tribe, each one head of his father’s household.

These then are the names of the men who shall stand with you: of the tribe of Reuben, Elizur the son of Shedeur;

of the tribe of Simeon, Shelumiel the son of Zurishaddai;

of the tribe of Judah, Nahshon the son of Amminadab;