The sons of Merari were the immediate male offspring of Merari, the third and youngest son of Levi. Mahli and Mushi were the first and second sons, respectively. These are the families of the Levites points back to the three sons and eight grandsons of Levi in verses 16-19, after whom the clans of their descendants were named. Contemporary English Version translates “All of the above were from the Levi tribe.” Families should be understood as “extended families” or “clans,” as in verse 14. According to their generations is the same word used in verse 16. (See the comment there.) In this case “with their descendants” clearly expresses the correct meaning.

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 .