וַיְצַ֤ו מֹשֶׁה֙ אֶת־הַלְוִיִּ֔ם נֹ֥שְׂאֵ֛י אֲר֥וֹן בְּרִית־יְהוָ֖ה לֵאמֹֽר׃
that Moses commanded the Levites, that bore the ark of the covenant of the LORD, saying:
Chizkuni
ויצו משה את הלוים, “Moses ordered the Levites, etc.” these are the Levites who had been mentioned in verse 9 as the “priests, who were the sons of the Levites;” Moses was not addressing the tribe of the Levites here. After all, the Levites at large were not charged with touching the Holy Ark, much less carrying it.