Webster(i)
40 And the LORD said to Moses, number all the first-born of the males of the children of Israel, from a month old and upward, and take the number of their names.
41 And thou shalt take the Levites for me (I am the LORD) instead of all the first-born among the children of Israel; and the cattle of the Levites, instead of all the firstlings among the cattle of the children of Israel.