G-d tells Moses to count the children of Israel and organize them into divisions

• G-d spoke to Moses in the Sinai Desert, in the Tent of Meeting on the 1st day of the 2nd month, in the 2nd year after the exodus from the land of Egypt, saying: “Take the sum of all the congregation of the children of Israel, by families following their fathers' houses; a head count of every male according to the number of their names. From 20 years old and upwards, all who are fit to go out to the army in Israel, you shall count them by their legions you and Aaron.
• Only the tribe of Levi you shall not number, and you shall not reckon their sum among the children of Israel. Appoint the Levites over the Tabernacle of the Testimony, over all its vessels and over all that belong to it; they shall carry the Tabernacle and they shall minister to it, and they shall encamp around the Tabernacle. When the Tabernacle is set to travel, the Levites shall dismantle it; and when the Tabernacle camps, the Levites shall erect it; any outsider [non Levite] who approaches shall be put to death. The children of Israel shall encamp, each man by his own camp and each man by his division. The Levites shall encamp around the Mishkan of the Testimony, so that there be no wrath upon the congregation of the children of Israel and the Levites shall keep the charge of the Mishkan of the Testimony.”
• “The children of Israel shall encamp each man by his division with the flag staffs of their fathers' house; some distance from the Tent of Meeting they shall encamp.”
• The Israelites did all that the Lord had commanded Moses; they encamped by their divisions, and so did they journey each man with his family, according to his father's house