How will we reconcile this Pasuk, which states that Yisrael should not ascribe their inheriting Eretz Yisrael to their own righteousness or to the evil of the seven nations, with Pasuk 5, which ascribes it to the evil of the seven nations?
Rashi: The Pasuk means that one should not ascribe it both to Yisrael's righteousness and the evil of the nations 1 but to the evil of the nations alone. 2
Ramban and Rashbam: The Pasuk means that they should not ascribe the destruction of the Cana'anim to their evil and their inheriting Eretz Yisrael to their own righteousness, 3 because whereas the first assumption is correct, the second one is not - as the Pasuk will explain in Pasuk 7 ?Z?chor Al Tishkach eis asher Hiktzafta? .
Seforno: The Pasuk means that, upon seeing the miraculous way in which they defeat the Cana'anim and they realize that Hashem is fighting on their behalf, they should not ascribe their victory to their righteousness, in order that they come and inherit the land quickly, because Hashem dispossesed the Cana'anim before us due to their evil. 4
In other words, the 'Vav' in "u've'Rish'as" means 'and', not 'or'.
Ramban: Which explains why He destroyed them, as the Pasuk goes on to explain.
Rashbam: Due to their superiority over other nations.
This is how the Seforno explains "u've'Rish'as ha'Goyim ha'Eileh ... " in this Pasuk - interpreting the 'Vav' as if it had written "Ki".
What is the connection between the current Pesukim and the previous Parshah?
How will we reconcile the current Pesukim, which describe Yisrael as unworthy and stubborn, with the Pasuk earlier in 7:8, which talks about Hashem's love of Yisrael?
Ramban: The current Pasuk is referring to this particular generation, which rebelled against Hashem from the moment they entered the desert, whereas the earlier Pasuk is referring to Yisrael in general.
Because the earlier Pasuk is referring to Yisrael when He took them out of Egypt, before they became rebellious.