The children of the third generation: this means the children who belong to the third generation. These are the grandchildren of any Edomite or Egyptian living in the land of Israel. So we may translate “and let their grandchildren be included….” The rendering “great-grandchildren” (Contemporary English Version) is not followed by other interpreters.

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on Deuteronomy. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .