Numbers 3:40
“And the Lord said unto Moses, Number all the firstborn of the males of the children of Israel from a month old and upward, and take the number of their names.”
But those that encamp before the tabernacle toward the east, even before the tabernacle of the congregation eastward, shall be Moses, and Aaron and his sons, keeping the charge of the sanctuary for the charge of the children of Israel; and the stranger that cometh nigh shall be put to death.
All that were numbered of the Levites, which Moses and Aaron numbered at the commandment of the Lord, throughout their families, all the males from a month old and upward, were twenty and two thousand.
And the Lord said unto Moses, Number all the firstborn of the males of the children of Israel from a month old and upward, and take the number of their names.
And thou shalt take the Levites for me (I am the Lord) instead of all the firstborn among the children of Israel; and the cattle of the Levites instead of all the firstlings among the cattle of the children of Israel.
And Moses numbered, as the Lord commanded him, all the firstborn among the children of Israel.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Cross-References
“And if it be from a month old even unto five years old, then thy estimation shall be of the male five shekels of silver, and for the female thy estimation shall be three shekels of silver.”
“Then Moses stood in the gate of the camp, and said, Who is on the Lord’s side? let him come unto me. And all the sons of Levi gathered themselves together unto him.”
“To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,”
“Notwithstanding in this rejoice not, that the spirits are subject unto you; but rather rejoice, because your names are written in heaven.”
“And it shall come to pass, that he that is left in Zion, and he that remaineth in Jerusalem, shall be called holy, even every one that is written among the living in Jerusalem:”