Why does the Torah begin the Parshah of Arayos with the prohibition against cursing one's father and mother?
Ramban: Refer to 20:9:2:2*.
Seforno: Because it is usually children who are born through adultery who curse their parents, and ultimately, it is those children who do not observe the Chukim and Mishpatim, in contravention of the Pasuk in Mishlei, 1:5 "Sh'ma B'ni, Musar Avicha". 1
Oznayim la'Torah #2: Because the Torah attributes to the Isur of a number of Arayos to the honor of one's parents. 2
Why does the Torah juxtapose 'Mekalel Aviv ve'Imo' to the previous Parshah?
Ramban #1 and Moshav Zekenim #1: Having taught us the Mitzvah of Mora Av va'Eim at the beginning of the Parshah, the Torah now teaches us the punishment of those who transgress it. 1
Ramban #2 and Moshav Zekenim #2 (according to Kabalah): Having stated in Pasuk 7 that He, in His capacity as our father and redeemer, sanctifies us ? "Vehiskadishtem Vih'yisem Kedoshim (Pasuk 7)" - whoever curses those who partner Him in our formation is Chayav Misah. 2
Oznayim la'Torah #1: Having just forbidden fathers to hand over their children to Molech the Torah now forbids children to curse their fathers.
Why does the Torah repeat the word "Ish"?
What if someone curses his father but not his mother, or vice-versa?
Sanhedrin, 67a #1 (citing R. Yonasan): Wherever the Torah does not say "Yachdav", it means both 'both' and 'either or'. 1
Sanhedrin 67a #2 (citing R. Yashiyah): One is Chayav - seeing as the Torah writes "Kilel" next to "Aviv" at the beginning of the Pasuk and next to "Imo" at the end of the Pasuk.
See Torah Temimah, note 14.
What are the implications of "Es Aviv ve'Es Imo"?
Sifra #1: "Es Aviv" - 've'Lo es Avi Aviv' (to preclude one's father's father); "es Imo", 've'Lo es Avi Imo' (topreclude one's mother's father). 1
Sifra #2: One is only Chayav for cursing Vaday Aviv and Vaday Imo, but not a Safek. 2
Why does the Torah repeat "Aviv ve'Imo Kilel"?
Rashi: To include the punishment for someone who curses his parents after their death. 1
Ibn Ezra and Moshav Zekenim: It teaches that he is guilty of a great abomination.
Sanhedrin, 85b: Otherwise we would learn from 'Makeh Aviv ve'Imo' that he is Patur - See Torah Temimah, note 18 & 19.
What does does Mekalel Aviv ve'Imo entail?
Targum Yonasan: It entails cursing them by the Great Name of Hashem (the Name 'Havayah').
What are the implications of "Damav bo"?
Rashi #1: Wherever the Torah writes "Damav bo" or "Demeihem bam", it refers to death by stoning. 1
Rashi #2: It implies that if he receives the death-penalty, he has only himself to blame.
Which we learn from Ov and Yid'oni at the end of the Sedra..
Why, in spite of the fact that all the Arayos are subject to Kareis - if there are no witnesses and in some cases even if there are - does the Torah decline to mention 'Kareis' specfically even once?
Hadar Zekeinim (in Va'eira, Sh'mos, 6:20): In deference to Moshe, who married his aunt.