1)
What does the Torah mean when it writes "Lo es Avoseinu Karas Hashem es ha'Beris ha'Zos ... "?
2)
Why does the Torah add the (otherwise superfluous) words "Kulanu Chayim"?
1.
Seforno: "You, who made the covenant with Hashem and who are now entering Eretz Yisrael, organize yourselves in a way that the forthcoming generations, who did not enter into the covenant, will fulfill what you are now undertaking.