Targum Onkelos and Targum Yonasan: 'This is the portion that is befitting for the Kohanim to receive' (because they earned it due to the deed of Pinchas).

Chulin, 130b: To teach us that the Matanos fall uunder the category of Din, and that consequently, if someone steals the Matanos from a Kohen, the Kohen can take the Ganav to Beis-Din. ¹

Chulin, 130b: It implies as long as the Matanos are intact, to exempt someone who damages or eats them from having to pay. ¹

Chulin, 130b: With reference to 18:3:0.1:2, it precludes Chazeh ve'Shok from the Din of "Mishpat" - in which case the Kohanim cannot claim them in Beis-Din. ²

Rashi: It precludes the animals of the Kohanim from the Din of Matanos. ¹

Ramban: It implies that this Mitzvah would only take effect upon their entry into Eretz Yisrael and they are allowed to Shecht Chulin, ¹ because as long as they were in the desert, they were only permitted to Shecht Kodshim, which were not subject to these Matanos.

Chulin 136a: It implies that the Kohen claims the Matanos directly from the Shochet ² even if he is a Kohen, ³ and not from the owner.

Sifri #1: It precludes an animal that is a T'reifah from the Din of Matanos. ⁴

Sifri #2; It precludes a Ger who has a Shechted animal from the time he was still a Nochri from Matanos. ⁵

Da'as Zekenim and Rosh: It refers to Chulin, since Kodshim are not subject to Zero'a, Lechayayim ve'Keivah.

Chulin 136a: "Zovchei (plural) ha'Zevach": Includes an animal of partners in the Din of Zero'a, Lechayayim ve'Keivah. ⁶

Rashi #1: To preclude a Chayah from the Din of Matanos.

Rashi (in Chulin, 135a): To teach us that, as opposed to Reishuis ha'Gez, which is confined to a sheep, it applies to both sheep (goats) and cattle. ¹

Chulin, 132b: "Im Shor" includes Kil'ayim (whose one parent is a goat, the other, a sheep) and "Im Seh", a Koy (which is neither a Beheimah nor a Chayah). ²

Chulin, 132a: To teach us that even an animal that is a partial lamb - if its mother is a lamb and its father, a deer, it is subject to half the Matanos. ³

Chulin, 33b: It implies that the owner must give it to the Kohen, but the Kohen is not permitted to take it. ¹

Sifri: It implies that the owner must give it to the Kohen himself - (meaning that the Kohen must eat it, and not give it to his animal to eat - Torah Temimah). ²

Rashi, Targum Onkelos and Targum Yonasan: "Zero'a" incorporates the right foreleg from the knee down to the foot; "Lechayayim", the two jaw-bones (the lower-jaw and the upper-jaw ? Targum Yonasan) together with the tongue, and "Keivah", the stomach (called the maw).

Rashi and Ramban #1 (both citing the Dorshei Reshumos, Chulin 134b) and Targum Yonasan (in Pinchas, 25:13): "Zero'a" corresponds to Pinchas' arm, which killed Zimri and Kozbi, "Lechayayim", to his Tefilah (see Tehilim, 106:30), and "Keivah", to their stomachs, which he pierced with his spear. See Bamidbar 25:8. (And the Mitzvah of Matanos was instituted on behalf of the Kohanim on the merit of Pinchas when he joined them in the Kehunah ? Ramban).

Ramban #2 (citing the Rambam in Moreh Nevuchim): Because they are all firsts - the jaws are the first limbs of the body, the Zero'a is the first of all the limbs that branch off from the body, and the stomach ¹ is the first of the innards. And it is befitting to give the firsts in honor of those who serve Hashem. ²

Chulin, 134b: The former implies the right foreleg, ¹ the latter, includes the hair on the head of the lambs and the beard of the goats. ²

Targum Yonasan: Because it incorporates both the lower and the upper jaws. ¹

Sifri: To confine Matanos to the lower jaw, which comprises two bones. ²

Chulin, 134b: Refer to 18:3:7:1**.

Chulin, 134b: It incorporates both the Cheilev that is on the stomach and the milk that is inside the stomach in the Din of Matanos. ¹

Rashi: Because they were only given to the Kohanim on the merit of Pinchas - after the episode of Korach. ¹

Ramban #1: Because the Torah there only included the Matnos Kehunah which are Kadosh, but not these Matanos and Reishis ha'Gez which are pure Chulin.

Ramban #2 (citing the Sifri): It did include them. ²