The sons of Kohath were the immediate male offspring of Kohath, the second son of Levi. Amram, Izhar, Hebron, and Uzziel are listed according to their age, Amram being the eldest. The years of the life of Kohath being a hundred and thirty-three years simply means that “Kohath lived 133 years.” (See the comment at verse 16.) It is possible to restructure this verse: “Kohath lived for one hundred and thirty-three years. His sons were….”

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 .