Granted, according to Rabbi Yonatan it is clear the punishment for adultery is strangulation, in the manner that Rabbi Yehuda HaNasi explains the reason for his opinion. But according to Rabbi Yoshiya, from where is it derived that there is a punishment of execution by strangulation in the world, i.e., in halakha, at all? Since this type of capital punishment is not mentioned in the Torah explicitly, say that decapitation by the sword is the least severe type, as it is mentioned in the Torah.

Rava said: The four types of the death penalty are learned as a tradition. There is no question as to the types of capital punishment that exist in halakha. Rather, the question is which type of execution is meted out as punishment for which sins.

The Gemara asks: What is meant by Rabbi Yonatan’s statement: It is not because strangulation is the most lenient type of capital punishment? The Gemara answers: At the root of the matter, Rabbi Yonatan and Rabbi Yoshiya disagree with regard to the issue that is the subject of the dispute between Rabbi Shimon and the Rabbis, i.e., whether strangulation or decapitation is the least severe type of execution. Consequently, Rabbi Yonatan does not employ the reasoning that strangulation is the least severe.

§ Rabbi Zeira said to Abaye: With regard to the rest of those transgressors, other than necromancers and sorcerers, who are stoned to death, with regard to whom stoning is not explicitly written in the Torah because their punishment is derived via a verbal analogy from that of a necromancer and a sorcerer, about which the verse states: “They shall be put to death, they shall stone them with stones, their blood shall be upon them” (Leviticus 20:27); through what verbal analogy is their punishment derived? Is it derived from the phrase “they shall be put to death,” or is it derived from the phrase “their blood shall be upon them”?

Abaye said to him: It is derived from a verbal analogy between “their blood” and “their blood shall be upon them.” As, if it is derived from “they shall be put to death,” why do I need the verbal analogy between “their blood” and “their blood”? Why does this term need to be written with regard to the various halakhot?

The Gemara asks: Rather, what is more reasonable? If it is derived from the verbal analogy between “their blood” and “their blood,” the same problem arises: Why do I need the phrase “they shall be put to death”?

The Gemara answers: This expression is necessary, as another halakha is derived from it. As it is taught in a baraita: The verse with regard to a murderer states: “He that smote him shall be put to death, for he is a murderer” (Numbers 35:21). I have derived only that the murderer is put to death with the mode of execution written concerning him, i.e., by decapitation. From where do I derive that if you cannot put him to death with the mode of execution written concerning him, e.g., if the condemned man will escape if one does not kill him, that you put him to death with any mode of execution with which you can put him to death? The verse states: “He that smote him shall be put to death [mot yumat],” the doubled verb teaching that he is put to death in any case, i.e., by any mode of execution.

This exchange between Rabbi Zeira and Abaye was subsequently discussed by later amora’im. Rav Aḥa of Difti said to Ravina: And if the halakha that there are transgressors other than necromancers and sorcerers who are punished by stoning is derived from “they shall be put to death,” what is difficult according to Rabbi Zeira? It appears from Rabbi Zeira’s question that he was troubled by the possibility that this halakha is derived from the phrase “they shall be put to death.”

If we say that the case of adultery of a married woman would pose a difficulty according to Rabbi Zeira, as it is stated: “The adulterer and the adulteress shall be put to death” (Leviticus 20:10), and therefore perhaps we should derive and learn from the phrase “they shall be put to death” stated with regard to a necromancer and a sorcerer that just as there, with regard to a necromancer and a sorcerer, they are executed by stoning, so too here, with regard to adultery, the transgressors should be executed by stoning, this does not pose a difficulty.

Rav Aḥa of Difti explains why it does not pose a difficulty: From the fact that the Merciful One states that a betrothed woman who committed adultery is executed by stoning, by inference we learn that a married woman who committed adultery is not executed by stoning, but rather she is executed by a less severe type of execution. Therefore, it could not have been derived from the case of a necromancer and a sorcerer that the punishment for the adultery of a married woman is execution by stoning.

And if it is rather the case of one who wounds his father or his mother that poses a difficulty according to Rabbi Zeira, as it is stated: “And he who smites his father or his mother shall be put to death” (Exodus 21:15), and therefore perhaps we should derive and learn from the punishment of a necromancer and a sorcerer that one who wounds his father or his mother should be executed by stoning, this too does not pose a difficulty.

Rav Aḥa of Difti explains why it does not pose a difficulty: Rather than deriving the punishment of one who wounds his father or his mother from a necromancer and a sorcerer, let us derive it from adultery with a married woman, as everywhere that the death penalty is stated in the Torah without specification you may not take it to be more stringent with regard to it, i.e., to mean that the sinner should be sentenced to a severe type of execution; rather, you must take it to be more lenient with regard to it, i.e., that a lenient type of execution should be applied. Since in both the case of adultery and the case of one who wounds his parent the type of execution is evidently not stoning, why was Rabbi Zeira troubled by the possibility that the source for execution by stoning in cases other than a necromancer and a sorcerer is derived from the phrase: “They shall be put to death”?

Ravina said to Rav Aḥa of Difti: It is the halakha concerning the rest of those who are stoned, themselves, which poses a difficulty according to Rabbi Zeira. This is because if their punishment is derived from the phrase “they shall be put to death,” then rather than deriving from the case of a necromancer and a sorcerer that these transgressors are executed by the severe method of stoning, let us derive from the case of one who commits adultery with a married woman, with regard to whom “they shall be put to death” is also stated, that they should be executed by strangulation, the less severe method. He therefore verified that it is derived from the phrase “their blood shall be upon them,” that they are executed by stoning.

MISHNA: These transgressors are those who are stoned to death: One who engages in intercourse with his mother; or with his father’s wife, even if she is not his mother; or with his daughter-in-law; or with a male; or with an animal; and a woman who engages in intercourse with an animal. And one who blasphemes, and one who engages in idol worship. And one who gives of his offspring to Molekh, and a necromancer, and a sorcerer. And one who desecrates Shabbat, and one who curses his father or his mother, and one who engages in intercourse with a betrothed young woman, and an inciter who incites individuals to idol worship, and a subverter who incites an entire city to idol worship, and a warlock, and a stubborn and rebellious son.

The mishna elaborates: One who unwittingly engages in intercourse with his mother who is also his father’s wife is liable to bring two sin-offerings for his intercourse with her: One due to the prohibition against engaging in intercourse with one’s mother and one due to the prohibition against engaging in intercourse with one’s father’s wife. Rabbi Yehuda says: He is liable to bring only one sin-offering, due to the prohibition against engaging in intercourse with one’s mother.

One who unwittingly engages in intercourse with his father’s wife while his father is married to her is liable to bring two sin-offerings: One due to the prohibition against engaging in intercourse with one’s father’s wife and one due to the prohibition against engaging in intercourse with a married woman. He is liable due to the former prohibition both during his father’s lifetime and after his father’s death, and whether the relationship between the woman and his father is one of betrothal or one of marriage.

Likewise, one who unwittingly engages in intercourse with his daughter-in-law during his son’s lifetime is liable to bring two sin-offerings for his intercourse with her: One due to the prohibition against engaging in intercourse with one’s daughter-in-law, and one due to the prohibition against engaging in intercourse with a married woman. The former liability applies both during his son’s lifetime and after his son’s death, and whether the relationship between the woman and his son is one of betrothal or one of marriage.

GEMARA: With regard to one who engages in intercourse with his mother, it is taught in a baraita that Rabbi Yehuda says: If his mother was not suitable for his father, as their marriage was forbidden, he is liable only due to the prohibition against engaging in intercourse with one’s mother, and not due to the prohibition against engaging in intercourse with one’s father’s wife.

This is clarified: What does it mean that she is not suitable for him? If we say that the mother and father were liable to receive the punishment of excision from the World-to-Come [karet], or liable to receive a court-imposed death penalty for their intercourse, in which case their marriage did not take effect and therefore Rabbi Yehuda holds that in this case there is no prohibition against engaging in intercourse with one’s father’s wife, this poses a difficulty. As accordingly, by inference, in may be understood that the Rabbis hold that there is such a prohibition even if she is not suitable for him. Doesn’t everyone agree that in such a case the father has no capability of betrothal with regard to her? Even if they cohabit, she is not considered his wife.

Rather, it is clear that Rabbi Yehuda is referring to a case where the father and mother are liable for violating a prohibition for their intercourse, but they are not liable to receive karet or capital punishment. And Rabbi Yehuda in this matter holds in accordance with the opinion of Rabbi Akiva, who says that betrothal does not take effect with those women with regard to whom one is liable for violating a prohibition if one engages in intercourse with them. The Rabbis disagree with this; in their opinion, betrothal does take effect in such cases, although a prohibition is involved. Therefore, the mother is considered the father’s wife, and the son is liable for engaging in intercourse with his father’s wife as well as for engaging in intercourse with his mother.

Rav Oshaya raises an objection to this explanation, as it is stated in a mishna in tractate Yevamot (20a): If a yevama is forbidden to her yavam by a prohibition resulting from a mitzva or by a prohibition stemming from sanctity, then since in these cases the levirate bond is not fundamentally nullified, she performs ḥalitza in order to become free of the levirate bond, and due to the prohibition she does not enter into levirate marriage.