In the Mincha davening of Shabbos we find a unique Tefilla, that "Your children should recognize and know that their rest (Shabbos rest) comes from You." By comparison, we don't daven that Hashem's children should recognize that the Mitzvohs of Tzitzis or Tefillin are from Him. What is so different about Shabbos that it needs this special tefilla?
Rabbi Yitzchak Hutner addresses this question in his magnum opus Pachad Yitzchak and gives the following explanation: We have Shabbos because Hashem had Shabbos, and we learn what it means to rest on Shabbos by emulating the Shabbos of Hashem. There is one technical problem. We didn't create the world, so how "in the world" do we emulate Hashem?
The answer is that Hashem formed the universe to serve as a place devoted solely and entirely to service of Him. The Mishkan, on a deeper level, is a microcosm of the world, and also was built solely and entirely for the service of Hashem. Therefore we can define our rest on Shabbos by what we were or not allowed to do in the process of building the Mishkan. Should there be any discrepancy between the role of the universe and Mishkan, we would no longer be able to derive the laws of rest on Shabbos from the Mishkan. Because if the world was not entirely the place to serve G-d, then we could not say that the building of the Mishkan, which is definitely solely a place of worship, is a reflection of creation. Therefore our resting from building the Mishkan would be in no way similar to the resting of G-d. Let us take this a bit further. All aspects of life in this world, even the mundane, have the potential to be utilized in service of G-d. We learn this from a verse in Mishlei (3:6) "B'chol d'rachecha da'eihu," "Know G-d in all your ways." This concept is expressed by our Rabbis in Avos (2:12), "All your actions should be for the sake of Heaven." This is the perspective one must have as he contemplates "and six days you shall work." The commandment to work is reflective of work's potential to serve a higher purpose.
The same criteria apply with regard to resting on Shabbos, albeit in a different manner entirely. All of Shabbos too must be devoted to serving G-d, for that is our task on Shabbos. Therefore the Prophet Yeshaya tells us, "If you proclaim Shabbos 'a delight...' and you honor it by not engaging in your own affairs, from seeking your own needs or discussing the forbidden..." Our Sages learn from this the concept of making Shabbos -"Shabbosdik." Changing the way we walk, the way we talk, and the manner of how we go about doing even the permitted gives our Shabbos the proper atmosphere. It also incorporates all that we do into our job of serving G-d on Shabbos. In fact, in this week's Parsha we learn that even the way we think should be "Shabbosdik."
The Meshech Chochma on the verse "Olas Shabbos b'Shabbato, the Olah offering of each Shabbos on its own Shabbos," explains that since we are forbidden from working on Shabbos, the possibility of committing a sin that will require a Chatas (sin offering) is less likely. Therefore a Chatas is not included in the Shabbos service in the Beis Hamikdash. On the other hand, because we are allowed to think about our business our minds are likely to wander and we might have forbidden thoughts. Therefore we are commanded to bring an Olah sacrifice, which brings forgiveness for forbidden thoughts, as part of the community Shabbos service in the Beis Hamikdash.
Changing the way we think can ensure the right mindset throughout Shabbos. We can now address our original question. In order to have Shabbos we have to understand Shabbos. Comprehending Shabbos means realizing that the world, the six days and Shabbos, each with its unique service, were created solely to serve G-d. Without that we would be missing the equation that connects the building of the Mishkan to the creation on the world and Shabbos. For this reason the Men of the Great Assembly prepared this special tefilla to help us truly understand Shabbos, and appreciate that it is a "rest that comes from you."