The building of the Mishkan was considered a great Mitzva which every person in B'nai Yisrael could contribute to. Still, our Rabbis teach us that it isn't the most important Mitzva in the Torah. Rashi says that the Parsha of Shabbat precedes the Parsha of the Mishkan to teach us that the building of the Mishkan is secondary to the observance of Shabbat. Yet, in Parshat Kedoshim when the Torah says, "Let every man fear his mother and his father, and keep My Shabbat," Rashi points out that even if your parents instruct you not to keep Shabbat, you still must keep Shabbat. Why in Kedoshim does Rashi make a similar point, even though the Torah does not mention Shabbat first? Also, why would we even think the building of the Mishkan takes precedence over Shabbat? The Kli Yakar explains the first question by reminding that both you and your father are required to observe Shabbat. But what about the second question? The Mechilta explains that we know that the Temple Service takes precedence over Shabbat (Korbanot are brought on Shabbat), so if the Temple Service (which is possible only with the construction of the Mishkan) takes precedence over Shabbat, then surely the construction itself takes precedence. The Torah therefore tells us that this is not so.