וַיְצַ֤ו מֹשֶׁה֙ אֶת־הַלְוִיִּ֔ם נֹ֥שְׂאֵ֛י אֲר֥וֹן בְּרִית־יְהוָ֖ה לֵאמֹֽר׃
여호와의 언약궤를 메는 레위 사람에게 명하여 가로되
Ibn Ezra
Although Moshe spoke only to the tribes of Reuven and Gad, he said I commanded you because they were a constituent part of Israel. Moshe speaks synecdochically in the opposite sense when he says to the Levites (in the passage beginning with “Take this book of the Torah” [31: 26]) “For I know your rebellious nature” [31: 27]: He was not then speaking only to the Levites, but to all Israel. However, since the Levites were included, he continued to address them.