What is this Pasuk coming to teach us?
Rashi: It teaches us that it is a Mitzvah to arrange the Yamim-Tovim 1 in such a way that all of Yisrael are able to celebrate Yom-Tov - in fulfillment of the Mitzvah of Aliyas Regel - by announcing a leap-year 2 in the event that the Galuyos have left Bavel and will arrive late in Yerushalayim. 3
Why is the Parshah of Yamim-Tovim, which applies equally to all of Yisrael, in Sefer Toras Kohanim?
Ramban: Because, although Yom-Tov per se applies to all of Yisrael, that of Korbanos, which the Pasuk mentions in connection with Yom-Tov, is applicable to the Kohanim in particular. 1
Ramban: See for example, Pasuk 8 and Pasuk 37.
Why are the Musafim not mentioned in this Parshah?
Ramban: Because Hashem did not intend them to bring the Musafim in the desert. 1
What are the connotations of "asher Tikr'u osam Mikra'ei Kodesh"?
Rashi: Refer to later, Vayikra, 32:35:1:1.
Ramban #1 and Seforno: The Yamim-Tovim are called "Mikra'ei Kodesh" because it is a Mitzvah to gather in Shul to publicly sanctify the day with Tefilah and Hallel, and dressed in one's finery, and to make it a day of festivity. 1
Ramban #2 (citing Targum #1 Onkelos) and Targum Yonasan #1: 'An occurrence of holiness' - On whichever day they occur, sanctify them.
Ramban #3 (citing the Sifri and Targum Onkelos #2): Make them special with regard to food and drink and fine clothes. 2
Rashbam, Targum Onkelos and Targum Yonasan: Whenever the term 'K'ri'ah' appears in connection with 'Mo'adim', it refers to the fixing of times. 3
What is the connection between this Parshah and the previous ones?
Seforno: After discussing the Korbanos and those who bring them, the purpose of which was to rest the Shechinah in Yisrael, 1 the Torah presents the Dinim of the Mo'ados, whose purpose is to desist from mundane activities, some completely, 2 others partially, 3 to enable us to study Torah and to indulge in holy pursuits - either completely, partially. 4 By doing so, one causes the Shechinah to rest in Yisrael. 5
Seforno: Shabbos and Yom Kipur.
Seforno: All the other Yamim-Tovim
What are the connotations of "Eileh heim Mo'adai"?