Why here did Moshe describe the Egyptians as pointing to Hashem's inability to bring Yisrael into Eretz Cana'an, whereas in Ki Sissa, he described them as pointing to the shtar Ra'ah, which stood against Yisrael the moment they left Egypt?
Ha'amek Davar: Because, whereas the Pasuk in Ki Sissa is referring to the Tefilah that Moshe Davened before he came down from Har Sinai the first time, which was to avert total annihilation - which the Egyptians predicted, the Tefilah here is referring to Hashem's decree to annihilate the current generation, but to let the children live - in which case the Egyptians would assume that Hashem, unable to drive out the Cana'anim, would build a settlement for the new generation in the desert, and that He killed the old generation because He hated them. 1
See Ha'amek Davar.
Why did Moshe insert here "u'mi'Sin'aso osam" - which he did not mention by the Meraglim in Bamidbar 14:26?
Ramban: He mentioned it here with reference to taking them out of Egypt - because when they worshipped the Eigel they were still close to Egypt and he was referring to how people would view the fact that Hashem took them out of Egypt in order to kill them 1 because He hated them. 2 This was not applicable however, by the Meraglim, when they were already on the verge of entering Eretz Cana'an, and only the argument that Hashem would be unable to take them into the land was applicable.
If Hashem hated Yisrael enough to kill them, surely He would not want to give them Eretz Cana'an. If so, how would this show His inability to take them into the land?
Da'as Zekenim, Hadar Zekenim (in Pasuk 24) and Rosh (in Pasuk 21): "u'mi'Sin'aso osam" is an alternative reason - as if it had written 'O mi'Sin'aso osam'.
