So Moses numbered all the firstborn males among the Israelites, as the Lord had commanded him.

Then the Lord said to Moses, “Number all the firstborn males of the Israelites from a month old and upward, and take ¹  the number of their names.

And they were as follows: The descendants of Reuben, the firstborn son of Israel: According to the records of their clans and families, all the males twenty years old or older who could serve in the army were listed by name individually.

And take ¹  the Levites for me – I am the Lord – instead of all the firstborn males among the Israelites, and the livestock of the Levites instead of all the firstborn of the livestock of the Israelites.”