(Mishnah): An Onen immerses and eats Pesach at night; this is forbidden regarding other Kodshim.

One who heard that he lost a relative [a while ago] or gathers bones [of a parent for reinterment - both of these mourn that day, but not at night] immerses and eats Kodshim [at night].

Beis Shamai say, if someone converted on Erev Pesach, he immerses and eats Pesach at night;

Beis Hillel say, one who takes leave of his foreskin (circumcises) is like one who takes leave of a grave (he requires Taharah like a Tamei Mes).

(Gemara) Question: Why is Pesach permitted but not Kodshim?

Answer: The Tana holds that Aninus applies mid'Rabanan at night;

Chachamim did not apply this stringency to Pesach, for which there is Kares [for not bringing it]; they apply their stringency regarding [eating other] Kodshim, which is a regular Mitzvas Ase.

(Mishnah): One who heard that he lost a relative...

Question: One who gathers bones [becomes Tamei Mes, he] needs Haza'ah on days three and seven!

Answer: It means, one who had someone gather bones for him...

(Mishnah): If someone converted...

(Rabah bar bar Chanah): They argue about an Arel Nochri [who circumcised and converted] - Beis Hillel decree, lest he will become Tamei Mes next Erev Pesach, and think that he can immerse and eat Pesach at night, just like this year (even though [presumably] he was exposed to Tum'as Mes before conversion, and never was sprinkled on);

He will not realize that this year immersion sufficed because he was not Mekabel Tum'ah while he was a Nochri, but next year he is Mekabel Tum'ah [and needs Haza'ah].

Beis Shamai do not decree.

All agree that if a Yisrael circumcises, he immerses and eats Pesach at night - we do not decree on account of an Arel Nochri (the Yisrael must immerse because until now he was forbidden to eat Kodshim - Chagigah 24B; see Tosfos Chodoshim).

Support (Beraisa - R. Shimon ben Elazar): Beis Shamai and Beis Hillel agree that if a Yisrael circumcises, he immerses and eats Pesach at night - they argue about an Arel Nochri:

Beis Shamai say, he immerses and eats Pesach at night;

Beis Hillel say, one who takes leave of his foreskin is like one who takes leave of a grave.

(Rava): Regarding Arel, Haza'ah and a knife, Chachamim upheld their enactments even regarding Kares (preventing bringing Pesach); regarding Onen, Metzora and Beis ha'Pras, they did not uphold their enactments regarding Kares (as we explain):

Arel - like above (one who converted on Erev Pesach is like a Tamei Mes, he may not bring Pesach);

Haza'ah (sprinkling Mei Chatas) is Shevus (forbidden mid'Rabanan on Shabbos), it is not Docheh Shabbos even if it is necessary to enable one to Metaher in time to offer Pesach;

A knife - (Beraisa): Just like one may not bring [a knife to circumcise on Shabbos] via Reshus ha'Rabim, it is forbidden via roofs, Chatzeros and Karfifos (enclosed areas without a roof, even though the Isur to transfer through these Reshuyos is mid'Rabanan; one who has not yet circumcised his son may not bring Pesach.)

Onen - like above (he may not eat Kodshim at night, but he may eat Pesach);

Metzora - (Beraisa): If the eighth day of Taharas Metzora fell on Erev Pesach, and he had an emission of semen on that day, he immerses and eats [Pesach at night]:

Normally, a Tevul Yom may not enter the Ezras Nashim - in this case, he may (to stick his ear, thumb and big toe into the Azarah to complete his Taharah and enable him to bring Pesach);

[Machshirim for] an Ase with Kares (Pesach) override an Ase without Kares (that a Tevul Yom must leave the Ezras Nashim).

(R. Yochanan): Mid'Oraisa, there is not even an Ase (for a Tevul Yom to leave)!

Question: "Va'Ya'amod Yehoshafat...b'Veis Hash-m Lifnei he'Chatzer ha'Chadashah" - why is it called new?

Answer: They made a new decree, that a Tevul Yom may not enter Machaneh Leviyah (i.e. Ezras Nashim).

Beis ha'Peras - (Mishnah): Beis Shamai and Beis Hillel agree that one may check a Beis ha'Peras (a field in which a grave was plowed, we are concerned that bones were dragged around) for one who wants to [go through to] bring Pesach, but not to eat Terumah. (Mid'Rabanan, a Beis ha'Peras is like a cemetery - to enable one to bring Pesach, we are lenient.)

Question: How does one check it?

Answer (Rav Yehudah): A person may walk through a Beis ha'Pras by bending down and blowing the dirt before each step [to clear away any small bones that might be there].

(Rav Yehudah bar Ashi citing Rav Yehudah): If many people walked through a Beis ha'Pras, it is Tahor (we assume that any bones have been crushed to less than the Shi'ur to Metamei, i.e. the size of a barley seed).

(Mishnah): If one was Tamei or far away and did not bring Pesach Rishon, he brings Pesach Sheni;

If he did not bring Pesach Rishon b'Shogeg or b'Ones, he brings Pesach Sheni.

Question: Since the law is the same, why does the Torah specify Tamei and Derech Rechokah?

Answer: These are exempt from Kares, and these (this will be explained) are Chayavim.

(Gemara - Rav Nachman): If one was far away and others slaughtered and did Zerikah for him [to come and eat at night], he fulfilled Pesach;

The Torah is merciful on (exempts) one who was far away, but if he brought Pesach, he will be blessed!

(Rav Sheshes): He was not Yotzei - he is precluded from Pesach, like a Tamei.

Support (Rav Nachman, for himself - Mishnah): If one was Tamei or far away and did not bring Pesach Rishon, he brings Pesach Sheni.

Inference: If he wanted, he could have brought Pesach Rishon (this refers to Derech Rechokah - since he is exempt, we must discuss a Tamei who could not bring Pesach)!

Rejection (Rav Sheshes - Seifa): If he was Shogeg or Ones and did not bring Pesach Rishon, he brings Pesach Sheni.

Question: Will you say that if he wanted, he could have brought Pesach Rishon - it says that he was Shogeg or Ones!

Answer: Rather, the Seifa discusses [without explicitly mentioning] Mezid with them (Shogeg and Ones);

Likewise, the Reisha discusses Onen with them (Tamei and Derech Rechokah; the Onen could have offered if he wanted)!

Support (of rejection - Rav Ashi - Seifa): These are exempt from Kares, and these are Chayavim.

Question: What case does this discuss?

It does not discuss Shogeg or Ones - they are not Chayav Kares!

Answer: Rather, it discusses Mezid and Onen.

Rejection: Rav Nachman can say that it only discuss Mezid;

Really, it should say Chayav (singular) - it says Chayavim for parallel structure with the Reisha, which says Peturim.