Mishnayos Kerisos Perek 3 Mishnah 5

בתו ואחותו – as, for example, he who has sexual intercourse with his mother and gives birth from this to a daughter, and she is his daughter and his sister from his mother, but his brother’s wife who was married to him prior to this and he died, and after his death, she married his father’s brother, and her father had sexual intercourse with her while she was a menstruant woman, and now we have the prohibition of his daughter and his sister that come as one. But even though she is illegitimate and prohibited to enter into the congregation/community [of the LORD], when she married to her father’s brother, the betrothal/Kiddushin was valid with her, because Kiddushin/betrothal takes effect in those who are liable for violating a negative commandment. Alternatively, if her father’s brothers were illegitimate/Mamzerim they are permitted to marry her ab initio, but she is prohibited to her father because of the prohibition of his brother’s wife because he is an additional prohibition, for at the outset, she was permitted to all the brothers of her father, and when she married to one of them, she became prohibited to all of the rest of the brothers [of her father], and because the name of brother’s wife takes effect regarding the rest of the brothers that she was permitted to him, the name of the brother’s wife also takes effect regarding her father to make her liable also because of the wife of his brothers. If his brother died and she married the brother of her father’s father, since it adds to her a prohibition regarding the rest of his father’s brothers, it adds to her the prohibition regarding himself. She would be a married woman, since she added a prohibition regarding the world (i.e., by being married), a prohibition added to her regarding him. If she became menstruous, since a prohibition was added regarding her husband, a prohibition was also added regarding him.

חייב עליה משום בת בתו וכלתו – as for example, when she married his son.

ואחות אשתו – when he married the daughter of his brother-in-law, who is the sister of his daughter’s daughter from/through the father.

ואשת אחיו – when his son died and she married the brother of this one.

ןאשת אחי אביו – that his brother died and she married his father’s brother.

אם עבר הזקן (if the grandfather transgressed) – the father of this one, and he married her, and afterwards, he had sexual relations with her, e is liable even on the [prohibition of] the father’s wife. But even though she is the wife of his brother, for we obligate him to an entity because of the wife of his father’s brother, so we see that she is forbidden to him, to his father because of her being his brother’s wife and she has no marital status with her, what are we dealing with here? As for example, when she fellow before him for a levirate marriage from his brother, who died without children and he engaged in levirate marriage and married her, but this grandfather who sinned who is taught in the Mishnah, which is because she is to him only a second level prohibition, because of the daughter of his son’s daughter and because of the wife of his son, because from the words of the Scribes, both of them are secondary relationships. But if you say that she is his daughter-in-law, we obligate him to an entity because she is the brother’s wife, which is not a refutation/objection, for one could establish that she is the brother’s wife of his son from his mother, and not the daughter-in-law of the father, but rather, the wife of his stepson and she is permitted to him. But if you should say, what prohibition is there that is added with the daughter of his daughter, when his father sinned and married her, for she is liable to him also, because of the prohibition of being the wife of the father, This matter is asked in the Gemara (Tractate Keritot 14b) and they answered that there is a son to the grandfather and he is the brother of that one (the Gemara uses the illustration of Ishmael dying without children and Isaac, his brother, who is the father of Jacob, engaged in a levirate marriage with Ishmael’s wife; but even though she is the wife of the brother of Jacob his son (i.e., Esau), she is not his daughter-in-law, for we are speaking here of the brother of Jacob from the mother, for he was not the son of Isaac), for since a prohibition was added through her regarding that son because of her father’s wife, a prohibition was added also regarding him.

וכן הבא על בת אשתו – he is liable for her because of of these that he is liable with his daughter.

ועל בת בת אשתו – he is liable because of all of those that he is liable for engaging in sexual intercourse with the daughter of his daughter. But the daughter of his wife who is his sister is found with her. As, for example, that his father either raped or seduced a woman and through her gave birth to a daughter, and afterwards he married the raped or seduced wife of his father who is permitted to him, for that daughter is his sister or the daughter of his wife. But the daughter of his wife’s daughter and the siser of his wife is found, as for example, that the father of his wife had sexual relations with the daughter of his wife, and she gave birth to a daughter, that daughter is the daughter of his wife’s daughter and the sister of his wife.