1 In fact in Sefer Devarim 9,5 as the Jews are
about to enter the land, God tells the Jewish
people that it is not because of their Yashrus
that they are entering the land, but because of
God's promise to the forefathers. This seems to
imply that yashrus is the necessary
characteristic required for inheriting the land
of Israel, and that were it not for the promise
to the forefathers the Jewish people would not
have gotten it.
2 Commentary of the Ramban at the end of
Achrei Mos
3 Commentary of the Alshich 35,10.