(Mishnah): An onlooker may kill any of the following to prevent them from transgressing:

A Rodef;

A man chasing a man to have Bi'ah with him, or a man chasing a Na'arah Me'orasah to rape her.

An onlooker may not kill someone chasing an animal for bestiality, or one who seeks to desecrate Shabbos, or to serve idolatry.

(Gemara - Beraisa) Question: What is the source that we may kill a Rodef?

Answer #1: "Lo Sa'amod Al Dam Re'echa."

Objection: We need this to teach the following!

(Beraisa): If Reuven sees Shimon drowning in a river, or being dragged by an animal, or being pursued by bandits, he must save him - "Lo Sa'amod Al Dam Re'echa." (Perhaps this is only if he can save without killing the bandits, or if they are not Yisraelim, but one may not kill a Rodef.)

Answer #2: We learn a Kal va'Chomer from Na'arah Me'orasah. We kill one who seeks to rape her, even though he intends only to blemish her. All the more so, we kill one who seeks to kill someone!

Objection: We do not punish based on a Kal va'Chomer!

Answer #3 (d'Vei Rebbi): We learn from a Hekesh from Na'arah Me'orasah - "Ki Ka'asher... u'Retzacho Nefesh (the law of Na'arah Me'orasah is like Rotze'ach).

Question: We do not learn Na'arah Me'orasah from Rotze'ach. The Torah explicitly says that we do not kill her, for she was Anusah!

Answer: The verse seems to learn Na'arah Me'orasah from Rotze'ach, but really, Na'arah Me'orasah teaches about Rotze'ach;

It equates Na'arah Me'orasah and Rotze'ach. Just like one can kill one who seeks to rape a Na'arah Me'orasah to save her, one can kill a Rodef to save the victim.

Question: What is the source to kill one who seeks to rape a Na'arah Me'orasah?

Answer (Tana d'Vei R. Yishmael): "V'Ein Moshi'a Lah" - if someone can save her, he does whatever is necessary (he may kill the rapist).

(Beraisa): If Reuven sees Shimon drowning in a river, or being dragged by an animal, or being pursued by bandits, he must save him - "Lo Sa'amod Al Dam Re'echa."

Question: A different verse teaches this!

(Beraisa) Question: If one is in danger of dying, what is the source that one must save him?

Answer: "Va'Hashevoso Lo."

Answer: From there, we would know that an onlooker must exert himself to save him, but we would not know that (if he cannot) he must hire others to save him;

"Lo Sa'amod Al Dam Re'echa" teaches that he must hire others.

(Beraisa): An onlooker may kill any of the following to prevent them from transgressing:

A Rodef;

A man chasing a man for the sake of Mishkav Zachar;

A man chasing a Na'arah Me'orasah (to rape her), or any other Ervah punishable by Misah or Kares.

We do not kill a Kohen Gadol chasing a widow, or a regular Kohen chasing a divorcee or Chalutzah (for these are only Chayavei Lavin).

If he already sinned with her, we do not kill him.

If someone can save her (without killing him), we do not kill him.

R. Yehudah says, even if she says 'do not pursue him, lest he kill me (before you kill him)', we do not kill him.

Question: What is the source of these laws (other than Rodef, which we learned above)?

Answer: "Vela'Na'arah Lo Sa'aseh Davar" - 'Na'arah' is spelled (without a 'Hei') like Na'ar, to teach about someone chasing a man;

'Na'arah' teaches about a Na'arah Me'orasah;

'Chet' teaches Arayos of Kares;

'Maves' teaches Arayos of Misah.

Question: Why must the Torah teach all of these?

Answer #1: Had it taught only Na'ar, one might have thought that we (kill to) save him because Mishkav Zachar is abnormal (and is a great disgrace), but we do not save a woman;

Had it taught only Na'arah, one might have thought that we save her from becoming defiled (she loses her virginity, and her husband will despise her), but we do not save a male;

Had it taught only these two, one might have thought that this is only because (Na'ar) is abnormal or (Na'arah Me'orasah) is greatly defiled, but we do not save other Arayos;

Therefore, 'Chet' is needed to teach other Arayos.

Had it taught only 'Chet', one might have thought that even Chayavei Lavin are included. Therefore, it says 'Maves.'

Had it taught only 'Maves', one might have thought that Chayavei Misah are included, but not Chayavei Kerisus. Therefore, it says 'Chet.'

Objection:: The Torah could have said 'Chet Maves', and it would not need to say 'Na'ar' and 'Na'arah'!

Answer #2: Indeed, that would suffice to teach all these cases;

Rather, 'Na'ar' excludes (one about to serve) idolatry. 'Na'arah' excludes bestiality and Chilul of Shabbos.

Question: According to R. Shimon, who says that we do kill someone about to serve idolatry, what do they exclude?

Answer: One of them excludes bestiality, and the other excludes Chilul Shabbos;

One might have thought to include Shabbos, from the Gezeirah Shavah "Chilul-Chilul" from idolatry. 'Na'ar' (or 'Na'arah') teaches that this is not so.

Question: According to R. Elazar b'Rebbi Shimon, who says that we kill someone about to serve idolatry or desecrate Shabbos, what do they exclude?

Answer: 'Na'ar' excludes bestiality. There is a tradition to pronounce it 'Na'arah' to correspond to the Parshah (which discusses a girl).

(Mishnah - R. Yehudah): Even if she says 'do not pursue him, lest he kill me', we do not kill him.

Question: What do they argue about?

Answer (Rava): They argue in a case that she does not want to be defiled, but prefers that they not pursue him, lest he kill her:

Chachamim say that the criterion is the Pegam, and she is concerned for this;

R. Yehudah says that the Torah allows killing him to save her life (perhaps she will resist and he will kill her). Here, she is not ready to sacrifice her life.

Question (Rav Papa): A Kohen Gadol defiles also a widow (he makes her a Chalalah, forbidding her to Terumah and Kohanim), yet we do not kill to save her!

Answer (Abaye): The Torah allows killing to save from a big Pegam, but not from a small one.

(Beraisa): 'Chet' teaches Arayos of Kares.

Contradiction (Mishnah): The fine (for raping or enticing a virgin Na'arah) applies (even) to one who has Bi'ah with his sister. (If he may be killed to save her, he would be exempt from the fine!)

Answer #1 (Rabanan): He cannot be killed once he did Ha'ara'ah (the first stage of Bi'ah). The fine is for completing the marital act (which breaks the Besulim).

Objection: This is like the opinion that Ha'ara'ah is touching (of the genitals);

However, like the opinion that it is entrance of the crown (of the Ever), this breaks the Besulim. Liability for the fine comes when he may be killed!

Answer #2 (Rav Chisda): The case is, he had abnormal Bi'ah with her (which is Pogem her but does not break the Besulim), and afterwards (when he may no longer be killed) he had normal Bi'ah with her (for which he must pay the fine).

Answer #3 (Rava): The case is, she told the onlookers not to kill him. The Mishnah is like R. Yehudah (that he may not be killed in such a case).

Answer #4 (Rav Papa): The case is, he enticed her (she consented). All agree that we do not kill him; he must pay the fine.

Answer #5 (Abaye): The case is, someone could have saved her without killing him. The Mishnah is like R. Yonason ben Sha'ul.

(Beraisa - R. Yonason ben Sha'ul): If the Nirdaf or an onlooker could have stopped the Rodef by maiming one of his limbs, but he killed him, he is (Rambam - worthy of being) killed for doing so.