I Chronicles 23:2 Midrash

וַיֶּאֱסֹף֙ אֶת־כָּל־שָׂרֵ֣י יִשְׂרָאֵ֔ל וְהַכֹּהֲנִ֖ים וְהַלְוִיִּֽם׃

And he gathered together all the princes of Israel, with the priests and the Levites.

Read midrashic interpretation of I Chronicles 23:2: and classical rabbinic exegesis.