Commento su Levitico 8:36

ויעש אהרן ובניו SO AARON AND HIS SONS DID [ALL THE THINGS] — This is stated to tell their praise — that they did not turn to the right nor to the left (cf. Sifra, Tzav, Mechilta d'Miluim 1 38).

AND AARON AND HIS SONS DID ALL THE THINGS WHICH THE ETERNAL COMMANDED BY THE HAND OF MOSES. Everywhere in this section it says ‘as’ the Eternal commanded Moses,²³¹Above, Verses 13, 17, 21, 29. The Hebrew text here reads: “as the Eternal commanded ‘by the hand of’ Moses.” But this expression I did not find in the Five Books of Moses, but in the Book of Joshua (14:2, etc.). And Ramban’s aim is clearly to distinguish everything that Moses did, which was exactly “as” G-d had commanded him, from that which the sons of Aaron did, as explained in the text. Hence it would seem to be correct that the reading in the text should be “as the Eternal commanded Moses.” It is so also in the Tur who quotes the language of Ramban. but here, since Aaron’s sons added to the command [by bringing strange fire which He had not commanded them],²³²Further, 10:1. He does not say it in this way, since they did not do as the Eternal commanded Moses. Rather, the verse states that they did all the things ‘which’ the Eternal commanded, and they further added to them “the strange fire” of which He said that He had not commanded them.²³²Further, 10:1.
Shemini

את כל הדברים אשר צוה ה' ביד משה, “all the matters which Hashem had commanded through Moses. Nachmanides writes that the reason the Torah does not use the customary wording of כאשר צוה ה' את משה, is because Aaron’s sons did not do exactly as G’d had commanded Moses, by adding strange fire, i.e. fire that did not originate in heaven. They had not been instructed to do this.

That they did not deviate. Otherwise, why does Scripture write, “[Aharon and his sons] fulfilled”? It is obvious! Would a righteous man such as he not do, Heaven forbid, as he was commanded by Hashem? Re’m writes: Similarly, the Sages expounded in the Mechilta, regarding (Shemos 14:2,4): “Speak to the Bnei Yisroel and have them turn back... They did just that.” And in Parshas Acharei Mos, regarding (16:34): “He did as Hashem commanded Moshe,” and in Parshas Bo, regarding (Shemos 12:28): “The Bnei Yisroel went and did...” and in Parshas Beha’aloscha, regarding (Bamidbar 8:22): “Just as Hashem had commanded Moshe.” However, in Parshas Beha’aloscha, regarding (ibid. 9:5): “So they made the Pesach offering ... [so did the Bnei Yisroel do],” the Sages did not expound. Perhaps this is because they relied on what was expounded concerning the [first] Pesach itself in Parshas Bo. It appears to me: The reason the Sages did not expound in Parshas Beha’aloscha, regarding (ibid.): “So they made the Pesach offering...” was because that entire section speaks of the Jewish people’s degradation, as Rashi explains: The entire forty years they were in the wilderness they made only this one Pesach offering, etc. For this reason the Sages did not expound concerning “So they made...” as they did elsewhere. Furthermore, Re’m writes: “However, in Parshas Korach (Bamidbar 17:26) regarding: ‘Moshe did so, [he did just as Hashem had commanded him],’ concerning the matter of the staffs, the Sages did not expound anything, and I do not know why.” It seems to me the answer is because it is not applicable to expound there: To tell you his praise, etc., since Moshe was the messenger of Hashem, and it is presumed that a messenger fulfills his assignment. It is no praise for a messenger when he does the assignment of the one who sent him. However, the Bnei Yisroel, and Aharon and his sons, did according to the words of Moshe. They made no changes from all that he commanded them, and they believed that Moshe was sent [by Hashem]. For this, it is apropos to expound: “To tell you their praise.” So it appears to me.