Numbers 4:38 Midrash

וּפְקוּדֵ֖י בְּנֵ֣י גֵרְשׁ֑וֹן לְמִשְׁפְּחוֹתָ֖ם וּלְבֵ֥ית אֲבֹתָֽם׃

And those that were numbered of the sons of Gershon, by their families, and by their fathers’houses,

Read midrashic interpretation of Numbers 4:38: and classical rabbinic exegesis.