1)
Why, in Pasuk 25, did the B'nei Gad and Reuven say "Ka'asher Adoni Metzaveh" and now switch to "Eis asher Tzivah Hashem"?
1.
Ramban: They were telling Moshe that it was unnecessary to make a two-sided stipulation, since his word was the word of Hashem. and that they would not dream of violating it.
2.
R. Bachye (on Pasuk 27) #1: In Pasuk 27 they said "Ka'asher Adoni Metzaveh" because they knew that, whatever Moshe said was the word of Hashem. 1
3.
R. Bachye (on Pasuk 27) #2: In the current Pasuk, they referred to Moshe by the Name of his Rebbe. 2
