Ramban: "Beneihem ... " is synonymous with "ha'Taf", and the Torah is clarifying here that the children, who do not understand, come to listen, and to ask questions, so that their parents should educate them. ¹

Seforno: Whereas "ha'Taf" refers to the small children who were too young to ask, "Beneihem" refers to when they grow older and are able to learn by asking their parents to explain to them what they heard previously, or to listen now and to ask.

Oznayim la'Torah: It is referring (not to Yir'as Hashem, which is not a Mitzvah that is connected to the ground, but) to the Mitzvah of Hakhel.