Albert Barnes Commentary Numbers 16

Amram and Izhar were brothers . Thus Korah, the son (that is, descendant) of Izhar, was distantly related by cousinship to Moses and Aaron.

Although Korah was a Kohathite, and therefore from the division of the Levites with the most honorable charge, he probably regarded himself as wronged. This was because Elizaphan, who had been made chief of the families of the Kohathites (Numbers 3:30), belonged to the youngest branch descended from Uzziel (Numbers 3:27). Consequently, Korah took the lead in this rebellion.

Of the others involved, On is not mentioned again; he probably withdrew from the conspiracy. Dathan, Abiram, and On were Reubenites. They were probably discontented because the birthright had been taken from their ancestor (Genesis 49:3), and with it the primacy of their own tribe among the tribes of Israel.

The Reubenites encamped near the Kohathites (Compare to Numbers 2:25 and the plan), and so the two families were conveniently situated for taking counsel together.

One pretext for the insurrection was probably to assert the rights of primogeniture—on the part of the Reubenites against Moses, and on the part of Korah against the appointment of Uzziel.

The “princes” appear to have belonged to the other tribes .

All the congregation are holy - Compare the marginal reference. Korah’s object was not to abolish the distinction between the Levites and the people, but to win priestly dignity for himself and his kinsmen (Numbers 16:10). This ultimate design is masked for the present in order to win support from the Reubenites by putting forward claims to spiritual equality on behalf of every Israelite.

“Seemeth” is not in the original. Render it as: Is it too little for you, that is, “is it less than your dignity demands?”

The words of Moses in his wrath are abrupt. The Aaronic priesthood was of divine appointment; and therefore, in rejecting it, the conspirators were truly rebelling against God.