Rashi: Refer to 18:6:3:2. It teaches us that Kohanim who come to the Beis-Hamikdash during Yom-Tov, even when it is not their turn to serve, share in the skins of the Korbanos of Yom-Tov and the meat of the Se'irei Chata'os of Yom-Tov. ¹

R. Bachye: It teaches us that the Kohanim who are serving in the Beis-Hamikdash on any particular day all share equally the skin, the flesh of the goats of the sin-offerings and the Matanos (the Chazeh ve?Shok) of the peace-offerings that are brought on that day.

Seforno: It teaches us that the Mishmaros (groups) of Kohanim, each of which served one or two weeks in the year in the Beis-Hamikdash, would only receive a portion in the Korbanos of the year what they traded with each other ² ('We will receive your portion this week, when we are serving, and the week that you serve, you will receive our portion'). ³

Succah, 26a: With reference to the Lechem ha'Panim, it teaches us that when Yom-Tov falls on Shabbos or on Shabbos in the middle of Yom-Tov, all twenty-four groups of Kohanim share in the distribution of the Lechem ha'Panim, which is only eaten. ⁴

Rashi #1 and R. Bachye #1 (citing the Sifri):: With reference to 18:8:1:1 - it precludes the Tamid and the Musaf of Shabbos during Yom-Tov and Nedarim and Nedavos, which the Kohanim whose turn it was that week sacrificed ¹ - which only the Kohanim whose turn it are permitted to parake of it.

Rashi #2 (on Bava Kama, 109b) It refers to the agreement that their fathers made in the time of David and Shmuel, when the Mishmaros of Kohanim were instituted, whereby the groups sold the rights to one another - 'You take your week and I will take my week!'

R. Bachye #2 (citing the Ibn Ezra): With reference to 18:8:1:2 - Besides a Kohen who sold the house that he inherited from his father - his fellow Koahanim cannot preclude him from sharing in the Korbanos of that day on the gounds that he is wealthy and doesn?t need it.

Seforno: With reference to 18:8:1:3 - it teaches us that during the year, when it is possible to exchange one week for another, the Avos instituted Mishmaros, where one group swaps with another.

Rashbam: It precludes a Kohen, who is permitted to bring a Korban even when it is not his turn to serve in the Beis-Hamikdash - and even ² on behalf of a relative from his father's family. ³

Targum Yonasan: It precludes what the Kohen leaves over after he has eaten, which he is permitted to sell to another Kohen. ⁴

Rashi: ?The Mishmaros were fixed in the days of David and Shmuel? - under their auspices.

R. Bachye: ?The Avos and the leaders of the generation who lived in the days of David and Shlomoh?.

Targum Yonasan: Elazar and Isamar, sons of Aharon. ¹

R. Bachye: To correspond to the three fixed ¹ groups of angels - each comprising twenty-four - known as ?Mishmaros? - who administer before Hashem daily (morning, afternoon and night) in Heaven and praise him. ^{2 3}