To whom are "Ervas Avicha" and "Ervas Imcha" referring?
Rashi: They refer to his mother who is his father's wife, and his mother who is not his father's wife, 1 respectively. 2
Ramban #1 and Moshav Zekenim #1 (both citing Sanhedrin, 54a): Both "Ervas Avicha" and "Ervas Achi Avicha" refer to the males (his father and his uncle) themselves. 3
Ramban #2 and Moshav Zekenim #2: "Imcha Hi" reveals that both refer to the man's mother. Through incest with his mother, he performs two evil deeds - revealing both Ervas Av and Ervas Em.
Targum Yonasan: They refer to a woman committing incest with her father 4 , and a man with his mother, respectively.
Sanhedrin, 54a: "Ervas Avicha" refers to one's father, 5 and "Ervas Imcha", to one's mother - whom his father raped or seduced. 6
But whom his father raped or seduced (Sifsei Chachamim).See also Oznayim la'Torah who explains why Rashi interprets the Pasuk like R. Yehudah, and not like the Chachamim.
See Torah Temimah, note 22, who queries Rashi.
Over whom the sinner transgresses two La'avin (for which, be'Shogeg, he is obligated to bring two Chata'os - Sahedrin, 54b), one for this La'av, and one for "ve'es Zachar Lo Sishkav Mishk'vei Ishah" (in Pasuk 22). Ramban and Moshav Zekenim: If so, why did the Torah not place a second La'av on being intimate with one's son and brother? Perhaps it is more concerned for the honor of elders. (If so, when a man is intimate with his son, the son transgresses two La'avim, and the father only one! - PF)
See Yayin ha'Tov, who asks why the Torah here teaches also the woman's Isur, bearing in mind that the entire Parshah discusses the man's Isur.
See answer #1.
See answer #2 and Torah Temimah, note 23.
Why does the Torah add "Imcha hi"?
Ramban: To stress that, by committing incest with his mother, he has performed two evil deeds, Ervas Av and Ervas Eim. 1
"Imcha Hi. Lo Segaleh Ervasah". Based on the first half of the Pasuk, why does the Torah not write 'Avicha ve'Imcha heim, Lo Segaleh Ervasam'?
Oznayim la'Torah: Having in mind what king Yehoyakim's mother said to him, when he had relations with her - 'I am is mother your mother! What pleasure can you derive from the place from which you emerged?' - the Torah is stressing that having relations with one's mother is purely Lehachis (to anger Hashem).
