Numbers 1:1-3

1Then the Lord spoke to Moses in the wilderness of Sinai, in the tent of meeting, on 1the first of the second month, in the second year after they had come out of the land of Egypt, saying,

2“2Take a 3census of all the congregation of the sons of Israel, by their families, by their fathers’ households, according to the number of names, every male, head by head

3from 4twenty years old and upward, whoever is able to go out to war in Israel, you and Aaron shall 5number them by their armies.