Numbers 1:1-3

The LORD spoke to Moses in the Meeting Tent in the Desert of Sinai. This was on the first day of the second month in the second year after the Israelites left Egypt. He said to Moses: “You and Aaron must count all the people of Israel by families and family groups, listing the name of each man. You and Aaron must count every man twenty years old or older who will serve in the army of Israel, and list them by their divisions.