Parshat ראה begins with the ceremony on הר גריזים and הר עיבל. The blessing was given on הר גריזים and the curse on הר עיבל. This was not merely a ceremony, but it reflected a covenant between Hashem and עם ישראל.
Rabbi Soloveitchik explained why it was necessary to have another covenant when the one on הר סיני was pretty special to say the least. The Rav said that the reason for this ברית, was to make ארץ ישראל an integral part of it.
Mount Sinai was considered the desert, and although instructions were given in Egypt, it was still חוץ לארץ. The Rav’s point here is very powerful. OUTSIDE OF ארץ ישראל, THE SANCTITY OF THE JEWISH PEOPLE IS WEAKENED!
The Land needed to participate in the covenant, because we must never forget the attachment we must have to the Land. Judaism’s components are עם ישראל, ארץ ישראל, ותורת ישראל. The people, the Land, and the Torah are integrated together to make us a holy nation.