R. Yirmeyah (to R. Zeira): I will explain both of our opinions:

You hold that we learn Todah from Shelamim (that it may come from Ma'aser; Rashi - that it may not come from Ma'aser wheat), which is learned from a Gezerah Shavah "Sham-Sham" from Ma'aser (Sheni);

Just like Shelamim is not itself Ma'aser, also Todah, but wheat bought from Ma'aser money may be used.

I agree that Todah is learned from Shelamim, which is learned from Ma'aser;

(However, I say) just like Shelamim does not come from a species subject to Ma'aser, also Todah (and its bread, i.e. one may not use wheat bought from Ma'aser money. Loaves bought from Ma'aser (Rashi Kesav Yad - l'Shem Todah) may be used. They are not considered a species subject to Ma'aser.)

(R. Ami): If one is Matfis Ma'aser Sheni for Shelamim (is Makdish it with Kedushas Shelamim), it does not take effect.

Question: What is the reason?

Answer: Kedushas Shelamim is not strong enough to be Chal (take effect) on Kedushas Ma'aser.

Question (Mishnah): If one used Ma'aser money to buy a Chayah for a Shelamim, or a Behemah to eat like Chulin, (this is improper, therefore) the skin does not become Chulin.

Inference: The skin receives Kedushas Shelamim!

Answer: No, it means, the animal is not Nitfas (bi'Kdushas Shelamim) in a way that would cause the skin to become Chulin (like it does when one buys a Behemah for Shelamim or a Chayah for Chulin, even though it was bought with Ma'aser money and the skin will not be eaten. Rashi - alternatively, the animal is not Nitfas bi'Kdushas Shelamim, so it is inapplicable to discuss the skin becoming Chulin.)

Question: What is the reason?

Answer (Rabah): This is like buying an ox for plowing (Kedushas Ma'aser transfers to the entire ox. It must be sold to buy food to eat bi'Kedushas Ma'aser.)

(R. Yochanan): If one is Matfis Ma'aser Sheni for Shelamim, it takes effect;

(R. Elazar): It does not take effect.

According to R. Yehudah, who says that one owns his Ma'aser Sheni (it is Chulin, just there are restrictions), all agree that Kedushas Shelamim is strong enough to be Chal;

They argue according to R. Meir, who says that Ma'aser Sheni is Kodesh. (One does not own it, he just has permission to eat it);

Clearly, R. Elazar holds like R. Meir;

Even R. Yochanan's law can be like R. Meir;

Version #1 (our text, Rashi Kesav Yad): Ma'aser is called Shelamim (it says "v'Achalta Sham (Shelamim)." A Gezerah Shavah teaches that this refers to an animal bought with Ma'aser.)

Version #2 (Rashi): Since Ma'aser can be (used to buy an animal to be) offered like Shelamim, it is Nitfas.

Question (against R. Elazar - Beraisa): If one is Matfis Ma'aser Sheni for Shelamim, when he redeems it, he must add two fifths, one for Hekdesh (it gets Kedushas Shelamim), and one for Ma'aser.

Answer: This is like R. Yehudah.

(Mishnah) Question: What is the source that if one said 'Alai Todah', he must bring it from Chulin?

Answer: It says "v'Zavachta Pesach... Tzon u'Vakar";

Objection: Pesach is not brought from cattle, only from flock (sheep or goats)!

Answer: This is extra, to equate (all other) Korbanos, which are brought from flock or cattle, to Pesach:

Just like Pesach is a Chovah (obligation), and it is brought only from Chulin, also all Chovos.

Therefore, if one said 'Alai Todah' or 'Alai Shelamim', now he is obligated to bring it, so he must bring it from Chulin.

In every case, Nesachim must be from Chulin. (Ma'aser cannot be used, for people do not eat them.)

(Gemara) Question: What is the source that one must bring Pesach from Chulin?

Answer #1 (Beraisa - R. Eliezer): We learn Pesach Doros (i.e. after entering Eretz Yisrael) from the Pesach offered in Mitzrayim;

Just like Pesach Mitzrayim was from Chulin (there was no Ma'aser (Rashi; Rambam - Hekdesh) at the time), also Pesach Doros.

R. Akiva: We cannot learn something possible (Pesach Doros, which (conceivably) could be brought from Ma'aser) from something impossible!

R. Eliezer: Indeed, we can learn possible from impossible.

R. Akiva: Blood and Eimurim of Pesach Doros must be offered on the Mizbe'ach. We cannot learn it from Pesach Mitzrayim, which was brought without a Mizbe'ach!

R. Eliezer: "Va'Avadta Es ha'Avodah ha'Zos ba'Chodesh ha'Zeh" - all Avodah of this month is the same. (Pesach Doros is like Pesach Mitzrayim.)

Question: If R. Akiva maintains that we cannot learn possible from impossible, his first objection suffices;

If he retracted, and does not learn from Pesach Mitzrayim because there was no (Hakravah on a) Mizbe'ach, he should learn from Pesach brought in the Midbar. (There was a Mizbe'ach, yet it was brought from Chulin, for there was no Ma'aser!)

Answer: He asks according to R. Eliezer's opinion;

I hold that we cannot learn possible from impossible;

You learn possible from impossible. Even so, you cannot learn from Pesach Mitzrayim because there was no Mizbe'ach! (Rashba - R. Akiva assumed that R. Eliezer learned specifically from Pesach Mitzrayim. For some reason, he could not learn from Pesach Midbar.)

R. Eliezer answered that the Hekesh "va'Avadta" overcomes this objection.

Question: Why didn't he answer that we learn from Pesach Midbar?

Answer: He answered according to R. Akiva's opinion:

According to me, we learn possible from impossible. Pesach Midbar answers your objection;

You do not learn possible from impossible. Even so, you should learn from Pesach Mitzrayim due to "va'Avadta"!

Question: Still, this is possible from impossible! (Why should R. Akiva agree to this?)

Answer (Rav Sheshes): We learn from this that we do not challenge a Hekesh (even if it contradicts normal laws of expounding (Tosfos - if there is nothing else to learn from it)).

Question (Rabanan of the Beis Medrash): How can Pesach Doros, which was learned from a Hekesh, teach about other Korbanos through a Hekesh?

Answer: "Va'Avadta" is not a Hekesh. Rather, it teaches that all Pesachim are one matter. They have one law.

Question: What is R. Akiva's source that Pesach must come from Chulin?

(The answer to this question is on Daf 83a. He expounds a verse. The Gemara first explains how R. Eliezer expounds the verse.)

(Shmuel citing R. Eliezer): "Zos ha'Torah la'Olah la'Minchah vela'Chatas vela'Asham vela'Milu'im ul'Zevach ha'Shelamim" teaches that just like Olah requires a Kli, all these Korbanos require a Kli. (This verse teaches about all Korbanos, even Ofos - Tosfos above, 2a.)

Question: Which Kli do we learn from this?

Suggestion: We learn that a Kli is needed for Kabalas Dam (like it says about the Olos offered before Matan Torah, "va'Yasem ba'Aganos").

Rejection: That verse applies also to the Shalmei Tzibur offered then! (R. Eliezer should have said that we learn from Olah and Shelamim.)

Answer: Rather, we learn that a knife is needed for Shechitah.

Question: What is the source that Olah requires a knife for Shechitah?

Answer: We learn from "va'Yishlach Avraham Es Yado va'Yikach Es ha'Ma'acheles Lishchot Es Beno."

"Va'Ya'alehu l'Olah Tachas Beno" - since the ram was an Olah in place of Yitzchak, it follows that also he was an Olah. (Sefas Emes asks why we do not learn from Hash-m's initial command to offer Yitzchak for an Olah.)