Zevachim, 70b: It is referring to the Neveilah of a Beheimah Tehorah. ¹

Rashi and Ramban: To preclude Cheilev from Tum'as Neveilah.

Zevachim, 70b: To include the Cheilev of a Shor ha'Niskal and of an Eglah Arufah in the exemption of Cheilev of Neveilah from Tum'ah ? even though it is Asur be'Hana'ah. ¹

Kerisos, 4a: To preclude the Cheilev of a Chayah and an Of from the Isur Cheilev. ²

Pesachim, 23a: They include even Meleches Hedyot in the Heter Melacheh ¹ and Taharah in the Cheilev of Hekdesh. ²

Rashi: To teach us that, in spite of the principle 'Ein Isur Chal al Isur'' (a new Isur cannot take effect on an existing one), the Isur of both Neveilah and T'reifah take effect on that of Cheilev, and are subject to Malkos.

Ramban (on Pasuk 25): Because we would otherwise have thought that Neveilah and T'reifah belong to the species from which one does not bring Korbanos ¹ and is therefore permitted to eat.

Zevachim, 70b: To extrapolate that it is only the Cheilev Neveilah of a Beheimah, where (by a Shechutah), the Cheilev is Asur but the Basar is permitted, which is Tahor; to preclude the Cheilev Neveilah of a Chayah, where the Cheilev and Basar (of a Shechutah) are both permitted, and whose Cheilev Neveilah is therefore Metamei like its Basar.

Sifra: "ve'Achol" teaches us that even though one is forbidden to eat it, one may feed it to a Nochri. ¹