Commentaire sur Le Lévitique 8:5

זה הדבר THIS IS THE THING [WHICH THE LORD COMMANDED ME TO DO] — The things you will see me doing in your presence has the Holy One, blessed be He, bidden me do, and do not think I am doing them for my own glory and for my brother’s glory. — The whole of this matter treated in the present chapter I have already explained in the Scriptural Reading beginning with the words, ‎‏ ואתה תצוה ‏‎(Exodus ch. XXIX.).

ויאמר משה …זה הדבר, Moses said:…"this is the word, etc." Moses informed the people of what G'd had said so that they would not register a protest at a later date claiming he had made all these appointments of his own accord. Seeing that the Torah reported here that everything was done at the command of G'd, Korach had no basis for the claim that he had acted inadvertently when he challenged Aaron's position seeing he had been present at this time and had not challenged Moses when the latter presented these appointments as having been made at the direct command of G'd.

The things which you will see. [Rashi is answering the question:] Nothing was mentioned earlier that Moshe could be referring to when he said, “This is the edict”! Therefore, Rashi explains: “The things which you will see.”