1)
What do the words, "all the words of Hashem..." come to include?
1.
Ramban #1: Moshe related to Aharon the entire contents of his communication with Hashem - including his refusal to undertake the Shelichus, and that ultimately, he was sent against his will.
2.
Ramban: (citing Midrash Chazis): He taught him the Names of Hashem. 1
1
As discussed earlier (See 3:14-15).