Numbers 1:2-6

²Take ye the sum of all the congregation of the children of Israel, after their families, by the descent from their fathers, by numbering the names, every male according to their polls;

³From twenty years old and upward, all that are able to go forth to war in Israel: these shall ye number according to their armies, thou and Aaron.

⁴And with you there shall be one man each of every tribe; a man who is the head of his family division.

⁵And these are the names of the men that shall stand with you; of Reuben: Elizur the son of Shedeur.

⁶Of Simeon: Shelumiel the son of Zurishaddai.