The sons of means the immediate male offspring of Izhar (verse 21) and Uzziel (verse 22), the second and third sons of Kohath, respectively. As grandsons of Kohath and first cousins of Aaron and Moses, the six men probably lived at the same time. Korah is the man who later rebelled against Moses (Numbers 16); Misha-el and Elzaphan appear briefly in Lev 10.4; but the names of the others are not mentioned again.

Quoted with permission from Osborn, Noel D. and Hatton, Howard A. A Handbook on Exodus. (UBS Helps for Translators). New York: UBS, 1999. For this and other handbooks for translators see here .