The concept of elevation of the day of Shabbos is also explained in the Maamor with the opening words וַיַקְהֵל מֹשֶׁה in the Alter Rebbe’s ‘Torah Ohr’ explaining the above-mentioned Rabbinic statement that asks about the juxtaposition of the Biblical instruction to keep Shabbos with the Biblical instruction to build the Mishkon, saying that this is because Shabbos is actually a preparation for building the Mishkon.
The crux of this explanation is that the reason for building the Mishkon is to draw down G-dliness from above to below into this world (as mentioned earlier) but since a person in this world is inside a physical body therefore, in order to cause a Divine Hamshocha from above he first needs an elevation. This is the concept of Shabbos, because on Shabbos all of the worlds have an elevation from below to above to the very highest of levels that is why Moshe prefaces the commandment of keeping Shabbos before he instructs on the building of the Mishkon.
