Which camp or camps is the Pasuk referring to?
Sanhedrin, 42b: It is referring to all three camps - Shechinah, Leviyah and Yisrael. 1
See Torah Temimah, note 27.
If the "Shom'im" refers to the witnesses, who heard the blasphemy, why does the Torah add the word "Kol"?
Rashi and Targum Yonasan: "Kol" comes to include the Dayanim, who heard the blasphemy repeated by the witnesses. 1
Sira: And we learn from "es Yedeihem" that each one of the witnesses and the Dayanim must place his hands on the head of the Mekalel independently. See also Torah Temimah and Malbim.
What is the significance of placing their hands on the sinner's head?
Rashi: They place their hands on his head and announce 'Your blood is on your head! We will not be punished on account of your death, and you have only yourself to blame!' 1
Da'as Zekenim and Hadar Zekenim, both citing the Sifra 2 : Witnesses about blasphemy must verbalize [the curse] as they heard it from the blasphemer. Moshav Zekenim - only one witness says the curse. (The others say 'I heard like him' - Sanhedrin 56a.) Therefore, they put their hands on him, and say 'this Aveirah that you cause us - it is on you!' Riva - this is like a Korban for all of them. He caused also those who heard to need to tear their clothes for hearing the curse. Gra (on Sifra) - also the judges hear it, from the witnesses. Through Semichah, they put the Aveirah on him, like we find in Semichah on the goat sent to Azazel!
This implies that the same applies to all hayvei Misah who are executed. However, the Ramban, and R. Shimshon and Ra'avad on the Sifra say that it is confined to the Mekalel. And the Moshav Zekenim citing the Maharam explains that we find Halachos that pertain to one specific case - such as an enticer and Ir ha'Nidachas. Consequently, also this can be different! Refer to 24:14:2:2. The Gemara did not discuss this Semichah. (PF)
Perhaps this is their Perush of Sifra; the text says 'you caused this to yourself.' Perhaps the other witnesses do Semichah just like the judges, for the blasphemer caused them to hear the curse. (PF)
What are the connotations of "Veragmu oso Kol ha'Eidah"?
Rashi: It means that the stoning was performed in the presence of the entire congregation (whose Shelichus they were carrying out). 1
And it was as if they had all stoned him. Rashi: From which we learn the principle that 'The Shali'ach of a person is like himself '.
What is the word "Oso" coming to preclude?
Moshav Zekenim (according to the Chachamim in Sanhedrin 45a): It implies a. that he is stoned without his clothes, 1 and b. that this is confined to a man but not to a woman, who is stoned clothed. 2
Chizkuni (according to R. Yehudah in Sanhedrin 45a): He is stoned without his clothes (and the same applies to a woman).
Torah Temimah - We extrapolate from the word "Oso", since the Torah did not write 'Yirgemuhu', like it did above in Kedoshim, 20:2.
Tosfos ha'Rosh (45a): We cannot make two D'rashos from one word! However, the Torah inserts "Oso" twice - once here (in the command), and once in Pasuk 23 (when they fulfilled it). Tosfos (45a): We do not extrapolate the Din of a woman from here; the Chachamim decreed it either on account of Hirhurim (lewd thoughts) of men, or on account of the shame of the woman.
