Numbers 1:2-4

Amplified Bible

² “Take a census of all the congregation of the sons of Israel, by their families (clans), by their fathers’ households, according to the number of names, every male, ^[a]head by head ³ from twenty years old and upward, all in Israel who are able to go out to war. You and Aaron shall number them, army by army. ⁴ And with you there shall be a man [to assist you] from each tribe, each being the head of his father’s household.