וְהַ֨לְוִיִּ֔ם לֹ֣א הָתְפָּקְד֔וּ בְּת֖וֹךְ בְּנֵ֣י יִשְׂרָאֵ֑ל כַּאֲשֶׁ֛ר צִוָּ֥ה יְהוָ֖ה אֶת־מֹשֶֽׁה׃
But the Levites were not numbered among the children of Israel; as the LORD commanded Moses.
Read midrashic interpretation of Numbers 2:33: and classical rabbinic exegesis.