John Wesley on Numbers 3:1

These - Which follow in this chapter. The generations - The kindred or family. Moses his family and children are here included under the general name of the Amramites, Nu 3:27, which includes all the children and grand - children of Amram, the persons only of Aaron and Moses being excepted. And the generations of Moses are thus obscurely mentioned, because they were but common Levites, the priesthood being given solely to Aaron's posterity, whence Aaron is here put before Moses, who elsewhere is commonly named after him. In Sinai - Nadab and Abihu, were then alive, though dead at the time of taking this account.