Numbers 3:1

These also are the generations. This is a common formula that occurs frequently in Genesis (Gen. 5:1; 6:9; 10:1; 11:10, 27; 25:12, 19; 36:1, 9; 37:2). It is a title used to introduce a new section of the narrative. “Generations” literally means “origins,” and is from the verb frequently translated “to bear,” “to bring forth,” “to give birth to.” It means the account or the history of the person or persons named.

Aaron and Moses. These men are set forth as the chosen heads of the tribe of Levi, which was selected for sacred service. One would expect the name of Moses to come first. But no descendants of Moses are mentioned; and as the passage deals only with the descendants of Aaron, his name takes precedence. Some have suggested that inasmuch as no descendants of Moses are mentioned, but only those of Aaron, Moses, as the one who gave them special instructions in regard to their sacred duties, was regarded as their spiritual father. The office of Moses, though higher than that of Aaron, was personal and not tribal, whereas Aaron was the progenitor of a long and distinguished line of priests.

In the day. An important day in the history of the Levites, it marks the point of time that saw the beginning of their organization and commission for the sacred duties of the church.

In mount Sinai. It may be there is a glance back to Ex. 24:1, where Nadab and Abihu are mentioned, though not as sons of Aaron (see Ex. 24:16; 31:18; Lev. 7:38; 25:1; 26:46; 27:34; Num. 28:6).