Numbers 3:17 Midrash

וַיִּֽהְיוּ־אֵ֥לֶּה בְנֵֽי־לֵוִ֖י בִּשְׁמֹתָ֑ם גֵּרְשׁ֕וֹן וּקְהָ֖ת וּמְרָרִֽי׃

And these were the sons of Levi by their names: Gershon, and Kohath, and Merari.

Read midrashic interpretation of Numbers 3:17: and classical rabbinic exegesis.