Rashi on Leviticus 6:13/רש"י על ויקרא ו׳:י״ג

1זה קרבן אהרון ובניו THIS IS THE OFFERING OF AARON AND HIS SONS — The ordinary priests, too, offer a tenth part of an ephah of flour on the day they are installed into the priestly service; the High Priest, however, offers one every day, as it is said, “a continual meal-offering, [half of it in the morning, and half thereof in the evening] etc. And the priest amongst his sons that is anointed in his stead (i. e. every high priest) [shall offer it]; it is a statute for ever” (Sifra, Tzav, Section 3 1-4; Menachot 51b).