To whom does "va'Heim" refer?
Rashi: To "Adascha" mentioned earlier in the Pasuk.
Rashi writes that "va'Hem" refers to "Adascha" mentioned earlier in the Pasuk. Why was "Atah va'Hem" repeated?
Riva citing R"M of Kutzi: Initially, Moshe told only Korach and his congregation to go. Korach said that their complaint was only against Aharon; they will go only if he goes. Moshe replied, you and them and Aharon.
Gur Aryeh: You must offer at the same time as Aharon. If not, they could say that there are times when Hashem does miracles - had we offered at the same time as Aharon, also ours would have been accepted, or [others will say] had Aharon offered at the same time as them, also he would have been burned.
Sifsei Chachamim: Initially, Korach thought that Moshe will go with them. Korach said that he should not, for their complaint was only against Aharon. Moshe replied, you and them and Aharon.