1)

(a)We already learned at the beginning of the Perek regarding the Pasuk "Vehayah ha'Sadeh be'Tzeiso ba'Yovel ki'Sedei ha'Cherem" that - we invert the Limud, to learn that if a Kohen declares his Sadeh Cherem Hekdesh, it goes to all the Kohanim of the Mishmar that is serving when Yovel enters, just like the equivalent case by the Sadeh Achuzah of a Yisrael.

(b)And, as we learned there, the Pasuk comes to counter the Kohen's argument that if with the advent of Yovel, he merits the property of a Yisrael that was not in his domain, how much more so property that he already owns. The Pircha on this argument is that - whereas in the former case, the Kohen only receives a portion together with the other Kohanim, here he is claiming the entire property, and, based on the principle Dayo ... , he ought not to receive more than he would have done in his source case).

2)

(a)Rami bar Chama therefore bases the Kohen's claim on the Pasuk "ve'Ish es Kodoshav Lo Yih'yu", which teaches us that - a Kohen can bring his own Korban whenever he wishes, and also eat it and take the skin. If not for Rami bar Chama's Pasuk, we would have thought that Charamim are considered like his Korban, which he may therefore take for himself.

(b)We reject Rami bar Chama's Limud however, on the grounds that a Korban is different - inasmuch as it is not in his domain, but is as if he was a guest at Hash-m's Table, as opposed to Charamim, which are in his domain.

(c)Rav Nachman therefore explains that we need the Pasuk to counter the Pasuk in B'har (in connection with the Arei ha'Levi'im) "ki Achuzas Olam hu lahem" - from which we would have learned that they always remain his.