פירוש על במדבר 8:22

כאשר צוה ה' ... כן עשו AS THE LORD HAD COMMANDED [MOSES CONCERNING THE LEVITES] SO DID THEY [UNTO THEM] — This is repeated (cf. v. 20) to tell the praise of those who performed the rite (Moses, Aaron and the Israelites) and those who had it performed on them (the Levites) — that none of them put any obstacle in the way.

כאשר צוה ה' את משה על הלוים, G’d had commanded that the task of the Levites would be to stand guard, to form the choir chanting the psalms and to carry the parts of the Tabernacle whenever the situation called for this. They would be assigned their immediate duties by Aaron and his sons.

No one objected. For if this were not so, why would this [phrase “so they did unto them”] be necessary, surely the Torah already stated that “Moshe did … [just as Hashem commanded]” (v. 20). Re’m writes that there is still a difficulty: This implies that because the Torah above wrote “Moshe did…” we infer both the praiseworthiness of those who did and those with whom it was done. If so, regarding the verse “Aharon did so” (v.3) where it does not previously write that he did so, one could say that this comes to teach about the matter itself — that he fulfilled the commandment that he was instructed, and that it does not to relate his praiseworthiness. One could ask a similar question in Parshas Beshalach (Shemos 14:4) where the Torah does not initially write that he did so, and in many other places – where they expounded in the same manner. It seems to me that certainly in any place where the Torah writes “he did so” or “they did so” it would not have been necessary to do so, because ordinarily the Jews fulfilled and accepted all mitzvos that Moshe commanded, and “he did so” is written only in order to recount their praiseworthiness. However here, if it were not for the phrase “as [Hashem] commanded” we would not have inferred their praiseworthiness from the phrase “Moshe did [all that Hashem commanded].” One would have said that it was necessary, to teach that they fulfilled the mitzvah, because one could not say that this was obvious. Hashem Himself had to make “effort” in this regard, instructing Moshe “take the Levites” (v.6) which Rashi explains as meaning “take them with words — fortunate are you…” Many prohibitions and death penalties were dependant upon this mitzvah and the firstborn Israelites had been disqualified from the service of Hashem. Therefore it was necessary, to teach that they fulfilled what He commanded. However, one cannot learn their praiseworthiness from here; therefore the verse writes “as [Hashem] commanded” to relate their praiseworthiness.

כן עשו להם, “so they did unto them.” The Levites did so to the priests. An alternate interpretation: “so did Aaron and his sons to the Levites.” This interpretation is based on Numbers 4,19: וזאת עשו להם וחיו, “this is what you are to do unto them so that they will live.”

כן עשו להם, Aaron and his sons would organise them, allocate to them their specific duties.