Why does the Torah write "Ish" twice here?
Torah Temimah (citing Sanhedrin, 57b): To include Nochrim, who are warned against immorality just like Yisrael. 1
Targum Yonasan: Refer to 17:3:1:1*.
See Torah Temimah.
Having opened the Pasuk with the words "Ish Ish", why does the Torah write "Lo Sikr'vu" in the plural?
Rashi (from Toras Kohanim): To include women on the Parshah of Arayos. 1
Despite the fact that they do not play an active role in the sin (Sifsei Chachamim).
Why does the Torah insert here "Ani Hashem"?
Rashi: To teach us that Hashem can be relied upon to reward those who desist from contravening the laws of Arayos. 1
Moshav Zekenim: (20:27): Parshas Arayos begins and ends with "Ani Hashem", both here and in Kedoshim, to show how strongly Hashem warned about them.
Even though they have not performed a positive action (Sifsei Chachamim).
Why does the Torah use the lengthy expression "Lo Sikrevu Legalos Ervah"?
Torah Temimah (citing the Toras Kohanim): Lo Sikrevu is a Lav against hugging and kissing Arayos. 1
Targum Yonasan: "Legalos Ervah" is a second prohibition -,against Bi'ah.
Why does the Torah always use the term "Legalos Ervah" (about incest and Nidah) to describe an immoral act?
Seforno: Because in the vast majority of cases, people are intimate for the pleasure that they derive from it. 1
Why does the Torah forbid marrying the Arayos?
Ramban, Moshav Zekenim (both citing the Rambam and Ibn Ezra) and Seforno: In order to minimize a person's desires and cut down on the time that one spends in intimacy, 1 the Torah forbids marrying those women with whom one otherwise tends to have the most 2 contact. 3
Seforno 6 : It is because the vast majority of people marry for pleasure - as the Pasuk states in Tehilim, 51:7. Consequently, if they were permitted to marry their close relatives, they would spend their time thinking about intimacy and the world would be full of immorality. 7
What does "She'er Besaro" mean?
Rashi (on Pasuk 17), Ramban, Seforno, Targum Onkelos and Targum Yonasan: It means 'his close blood-relative'. 1
According to the Seforno, it refers to the first-level offspring - such as the sister of one's father (who are both children of the same father [See Seforno]).
What is the significance of the word "She'er"?
Why does the Torah add the words "Lo Sikr'vu"?
Why does the Torah always use the term "Legalos Ervah" (by incest and Nidah) to describe an immoral act?