Why was this Parshah not said immediately after the Mishkan was completed (on the first of Nisan), seeing as was important for the camp of Yisrael to be holy and fit for the Shechinah to dwell in it (Ramban)?
Rashi: It was, 1 even though the Torah only inserts it here.
Rashi (citing Gitin, 60a): As were seven other Parshiyos
Why does the Torah mention the word "Machaneh" three times
Rashi (based on Pesachim, 67a): They represent Machaneh Shechinah (inside the hangings of the Mishkan itself); 1 Machaneh Leviyah (surrounding the Mishkan, where the Levi'im encamped) 2 and Machaneh Yisrael (surrounding Machaneh Leviyah), 3 where the four Degalim encamped.
Rashi: Which all three listed Teme'im were forbidden to enter
What exactly does "v'Chol Tamei la'Nafesh" mean?
Rashi: Targum Onkelos 'di'Msa'av li'Tmei Nafsha de'Enasha' means 'Anyone who became Tamei via the bones of a Mes. 1
Rashi: Li'Tmei refers to bones, as we find in Midrash Rabah 'Adriyanus Shachik Tamya'.
QUESTIONS ON RASHI
Rashi writes that this Parshah was said on the first of Nisan). Why was it written only here?
Ramban: Since the Torah counted the families of Yisrael and to the house of their fathers and separated the Eirev Rav from their midst, it is appropriate to conclude the law of Asham Gezeilos, including the law of Gezel ha'Ger that now came into effect.
Rashbam: Since it deals with sending Teme'im out of the camp, it was said as soon as the camps of Yisrael and of Levi were organized.
Rashi writes that the Targum means one who became Tamei via the bones of a Mes. What forced him to say so?
Riva: If [the Targum 'Tamya'] were an expression of Tum'ah, it would have said "li'Mesa'av Nafsha d'Insha', like it translates every Tum'ah in the Torah. 1
Riva: It the Targum were an expression of Tum'ah, it would mean one who became Tamei via a Tamei Mes. Mizrachi - this cannot be, for such a person is not an Av ha'Tum'ah, and Tamei la'Nafesh was taught with Zav and Metzora, who are Avos.
Mizrachi: If so, it cannot mean bone, for the Targum of bone is always 'Garma'!
Rashi writes that eight Parshiyos were said that day. One of them was Parshas Temei'im (Gitin 60a), i.e. Pesach Sheni (Rashi 60a). The Gemara says that Moshe taught about Pesach Sheni on Pesach Rishon, a month beforehand!
Moshav Zekeinim citing R. Tam: Parshas Temei'im is the Isur of a Tamei to entered the Mikdash or eat Kodshim or Terumah.