What is the Torah learning from Chatas?
Torah Temimah (citing Zevachim, 11a): Asham, like Chatas, requires the owner to perform Semichah.
Whom is "ha'Kohen asher Yechaper bo" coming to preclude?
Rashi: It is coming to preclude a T'vul-Yom, a Mechusar Kipurim and an Onan, who are not fit to perform the Avodah, from receiving a portion of the Asham.
Why does the Torah see fit to inform us the ages of Moshe and Aharon?
Rashi (in Sotah, 12a): Because it was in the same year that Yisrael left Egypt.
Seforno: To teach us (with reference to the previous Pasuk) that despite their advanced age, they hurried to perform the will of Hashem with alacrity. 1