These also [are] the generations of Aaron and Moses
The descendants of them, those of the former, who is named first, because the eldest, were priests, and those of the latter Levites, and who are not very plainly pointed at, but are included among the Amramites, ( Numbers 3:27 ) ; the posterity of Moses being very obscure, only Levites, and these not particularly named but swallowed up among the Kohathites: find the following account was as it stood,
in the day [that] the Lord spoke with Moses in mount Sinai;
and not, altogether as it then, was when he spoke to him in the wilderness, of Sinai, for then Aaron had four sons, but now two of them were dead as is after observed; and it seems to be for the sake of this circumstance chiefly that this clause is so put.