What is "the fat of the land" referring to?
Rashi: Italy of the Greek Empire - incorporating Rome.
What are the ramifications of the Berachah, "v'Al Charbecha Tichyeh"?
Ramban: That Esav will vanquish other nations, and that he himself will be unconquerable. Only Yisrael will be able to stand up to him - until he will be in pain. 1
Why did Yitzchak bless Yaakov (27:28) with "mi'Tal ha'Shamayim," and to Esav he added the word "me'Al"?
Magid Meisharim: Esav will get only from Shamayim over him, i.e. Keneses Yisrael. Yaakov will get even from me'Al me'Al (the upper Shamayim).
Why does it say "Yitzchak Aviv"?
Ohr ha'Chayim, Malbim: This explains why he blessed him, due to fatherly love; when Esav cried, Yitzchak's mercy was aroused.
Why does it say "Hinei"?
Ohr ha'Chayim: Esav has only what is in front of him (this world). Yaakov has also the eternal world.
Why did he say "mi'Shemanei ha'Aretz Yihyeh Moshavecha"? He did not say so to Yaakov!
Refer to 27:28:2:1.
Ha'amek Davar (to 27:28): Yaakov's Berachah was with Ru'ach ha'Kodesh. It was not needed for Yaakov, for he will receive Eretz Yisrael. He needed only that the Peros be blessed, and that they be grain and wine, the staples of human life.
QUESTIONS ON RASHI
Rashi writes: "'Of the fat of the earth etc.' - This refers to Italy, of Greece." Why explain the blessing as specific to one place?
Gur Aryeh: Yitzchak made Esav's blessing dependent on "Moshavecha," "your dwelling place," which Rashi specifies. Yaakov's blessing specified that the blessing is from HaSh-m, not dependent upon any one location.