Why does the Torah write "Vehikriv mi'Zevach ha'Shelamim" and not "Vehikriv Mimenu"?
Sifra: To teach us that if one Shechts the 'Shelamim she'Lo li'Shemo, it is nevertheless Kasher.
What is the definition of "Cheilev" - as opposed to Shuman"?
Ramban and Moshav Zekenim (both in Pasuk 9): 'Cheilev' is fatty membranes that peel off from the animal's flesh easily, whereas 'Shuman' is the fat that is closely attached to the flesh. 1
As the Pasuk indicates in Ha'azinu Devarim, 32:15 and in many other places (Ramban).
What does "Cheilev asher al ha'Kerev" incorporate?
Chulin, 93a: It incorportaes the Cheilav that is on the Hemses (the first stomach of the ruminate) and on the Beis ha'Kosos (the second stomach of the ruminate). 1
See Torah Temimah, note 21.
What is "ve'es Kol ha'Cheilev ... " coming to include?
Rashi #1 (citing R. Yishmael 1 in the Sifra): It comes to include even the Cheilev on the maw (the stomach) 2
Rashi #2 (citing R. Akiva 3 in the Sifra): It comes to include the Cheilev on the intestines exclusively. 4 Refer to 3:3:1:1.
Chulin, 49b: To qualify as Cheilev, the fat must be a. spread, b. a membrane and c. easily peeled - like the Cheilev that is on the maw. 5
Moshav Zekenim (citing R. Yishmael in Chulin, 49b): Just like the Cheilev covering the Kerev is a membrane that can be peeled off, also all such Cheilev (of a Shelamim is offered, and is forbidden to eat even in Chulin).
And certainly the Cheilev on the intestines (Sifsei Chachamim).
The Sifra actually switches the opinions
See Torah Temimah, note 20.
Why must the Cheilev be burned on the Mizbe'ach?
Moshav Zekenim #1: To atone for sin that one does amidst obesity - "va'Yishman Yeshurun va'Yiv'at" (Devarim 32:15). It is therefore considered as if the owner offered his own Cheilev on the Mizbe'ach.
Moshav Zekenim #2: The Cheilev on the Kerev, which is full of excrement, should come and atone for the sin of a man full of reeking odors; the two kidneys, which counsel, for the kidneys that counsel sin and deceit, and the Yoseres ha'Kaved, for having hardened one's heart and ears.