Why did the Levi'im need to do the Avodah 'in front of Aharon and his sons'?
Oznayim la'Torah: Because, due to the circumstances, they were lacking the five years apprenticeship that Levi'im were destined to require. Consequently, Aharosn and hs sons had to keep check on them that they performed everything correctly.
Why does the Torah need to inform us again that they did to the Levi'im all that Hashem had commanded Moshe?
Rashi: In praise of all those who were involved, inasmuch as not one of both those who did and those to whom it was done, objected. 1
Seforno: To inform us that they carried out everything that Hashem commanded them earlier. 2
Oznayim la'Torah: It repeats it with respect to Yisrael, who performed their role in inaugurating the Levi'im, despite the sadness in losing their rights. 3
