Sanhedrin 54A

תניא כוותיה דרבא: ״איש״⁠ – פרט לקטן.

§ It is taught in a baraita in accordance with the opinion of Rava: With regard to the verse: “And the man who lies with his father’s wife, he has uncovered his father’s nakedness; both of them should be put to death, their blood should be upon them” (Leviticus 20:11), the term: “The man,” excludes a minor.

״אשר ישכב את אשת אביו״⁠ – משמע בין אשת אביו שהיא אמו, ובין אשת אביו שלא אמו. אמו שאינה אשת אביו מניין? תלמוד לומר: ״ערות אביו גלה״, מופנה להקיש ולדון ממנו גזרה שוה.

The phrase “who lies with his father’s wife” indicates that he is liable to receive capital punishment whether she is his father’s wife who is his mother or whether she is his father’s wife who is not his mother. From where is it derived that he is liable in a case where she is his mother who is not his father’s wife? The verse states: “He has uncovered his father’s nakedness.” Although this phrase does not relate directly to the case of one’s mother who is not his father’s wife, the halakha in this case is derived from this phrase as it is free, i.e., the phrase is superfluous in this context, and is evidently included in the verse in order to compare between the two cases and learn a verbal analogy from it, as the baraita will elaborate below.

״מות יומתו״⁠ – בסקילה. אתה אומר בסקילה, או אינו אלא באחת מכל מיתות האמורות בתורה? נאמר כאן ״דמיהם בם״, ונאמר באוב וידעוני ״דמיהם בם״. מה להלן בסקילה, אף כאן בסקילה.

From the phrase “both of them should be put to death” it is derived that they are executed by stoning. The baraita asks: Do you say that that they are executed by stoning, or is it rather by one of all the other types of the death penalty that are stated in the Torah? The baraita answers: It is stated here: “Their blood should be upon them,” and it is stated with regard to a necromancer and a sorcerer: “Their blood should be upon them” (Leviticus 20:27). Just as there the verse states that a necromancer and a sorcerer are executed by stoning, so too here, with regard to one who has sex with his father’s wife, the transgressors are executed by stoning.