Halakhah su Levitico 18:10

To not reveal the nakedness of the daughter of the son: To not reveal the nakedness of the daughter of the son, as it is stated (Leviticus 18:10), "The nakedness of the daughter of your son, etc. do not reveal." And according to what appears, the prohibition is whether the son is fit or even if he is a mamzer - he is his son regardless - and whether the daughter of the son is fit or even if she is a mamzeret.

To not reveal the nakedness of the daughter of the daughter: To not reveal the nakedness of the daughter of the daughter, as it is stated (Leviticus 18:10) "or the daughter of your daughter, you shall not reveal, as it is your nakedness." All of its laws are like the law of the daughter of the son; and the ones secondary to her are also the daughter of the daughter of daughter and, likewise the daughter of the son of the daughter. And some say that there is no end to [the generations of] these prohibitions ever.

He prohibited us from sexual intercourse with the daughter herself. But this was not explicitly made clear in the Torah; and, "the nakedness of your daughter you shall not uncover," did not appear in Scripture. However since it mentioned the daughter of the son and the daughter of the daughter, you can take it as a proof to clarify the matter and reveal it: Since He forbade the daughter of the son and the daughter of the daughter - all the more so, the daughter [herself]! And in the Gemara of Yevamot (Yevamot 3a), they said, "[With regard to] his daughter, the main aspect of this prohibition is derived by homiletical interpretation. As Rava said, 'Rav Yitzḥak bar Avdimi said to me, "[This prohibition is derived by means of a verbal analogy of the words,] theirs (hena), and they (hena); and lewdness (zimah) and lewdness (zimah)."'" [This] means to say that He said about the daughter of your son and daughter of your daughter, "for theirs (hena) is your own nakedness" (Leviticus 18:10). And He [also] said about the prohibition of a woman and her daughter and the daughter of her son and the daughter of her daughter, "they (hena) are kin; it is lewdness" (Leviticus 18:17). Just like with the prohibition of a woman and her daughter, her [actual] daughter is forbidden; so [too] with the prohibition of a daughter of his son and the daughter of his daughter, is his [actual] daughter also forbidden. And He said about the punishment of "a man who took a woman and her mother, it is lewdness; they shall be burned in fire, he and them" (Leviticus 20:14). [So] likewise is a woman and the daughter of her son and the daughter of her daughter [punished] with burning, because, "lewdness," appeared [also] about them - so we learn it from the verbal analogy [created by the common use of the word,] zimah. And regarding this punishment, the same is the law for his daughter and the daughter of his son and the daughter of his daughter. As we learn it about them from the verbal analogy [created by the common use of the word,] hena. For hena is written about the daughter of his son and the daughter of his daughter, just like it appears with a woman and her daughter. And the language of the Gemara, Keritot (Keritot 5a), is, "A verbal analogy should never be regarded lightly in your eyes, as [the prohibition of] one’s daughter is one of the essential laws of the Torah, and Scripture taught it only through a verbal analogy. It came from [the common use of] hena, and [the common use of] zimah." And understand their saying, "Scripture taught it only," and not saying, "and they (the Rabbis) taught it only" - for all of these things are a tradition from the prophet (Moshe), peace be upon him. It is an explanation that was received, as we explained at the beginning of our great composition, the Commentary of the Mishnah. However Scripture [itself] refrained from mentioning it, since it was possible to have it learned from a verbal analogy. And that is the content of their saying, "Scripture taught it only through a verbal analogy." And it is sufficient that they said, "one of the essential laws of the Torah." Behold it is explained from all that precedes that one who transgresses the negative commandment of his daughter and the daughter of his daughter and the daughter of his son is [punished] with burning. But if the testimony was not ratified, it is with excision if it was volitional. And if he was inadvertent regarding one of them, he must sacrifice a fixed sin-offering.