Rashi on Leviticus 8:2/רש"י על ויקרא ח׳:ב׳

1קח את אהרן TAKE AARON — This section was spoken seven days before the final erection of the Tabernacle and so should have been placed before Exodus XL., but a transposition of this kind is quite customary in the Bible, because there is no “earlier” or “later” (no chronological order) in the Torah.

2קח את אהרן means win him over with fine words and draw him on (cf. Rashi on Exodus 14:6) (Sifra, Tzav, Mechilta d'Miluim 1 2)).

3ואת פר החטאת וגו'‏‎‎‎‎‎ AND THE BULLOCK FOR THE SIN OFFERING [AND THE TWO RAMS] etc. — These are the sacrifices mentioned in the section containing the command about the installation ceremony — in the Scriptural Reading beginning with the words, ואתה תצוה (see Exodus 29) and now, on the first day of the installation ceremony He again admonished him (Moses) regarding this when the time for performing the command arrived.