1)
Why does the Torah write "Vayismoch (singular) Aharon u'Vanav' here ? in connection with the Chatas, and "Vayism'chu ... " (plural) in Pasuk 18 ? in connection with the Olah?
1.
Oznayim la'Torah: Because by the Viduy (the major part of the Semichah) on the Chatas, Aharon was confessing on his part of the Chet Eigel. Consequently, the Torah writes "Vayismoch" (with reference to Aharon, adding that his sons who did not participate in that sin sait Viduy too; whereas by the Olah, Aharon's was not basically different than his sons, the Torah writes that they (all) confessed.
