What are the connotations of the word "Lehashmido"?
Rashi: "Lehashmido" means that his children would die 1 - as opposed to 'Lehargo', which would have meant that he would die.
What is the word "Gam be'Ad Aharon" coming to include?
Rashi: It includes Aharon's children, on whose behalf Moshe also Davened and two of whom his Tefilah saved.
Why did Moshe's Tefilah not also save Nadav and Avihu?
Pesikta Rabasi, 47: Because (sometimes) Tefilah achieves half of one's request. 1
This is - as the Midrash Rabah explains -'Tefilah As'sah Mechtzah'.
Why did Moshe juxtapose his Tefilah on behalf of Aharon to the burning of the Eigel ha'Zahav?