In his Likutei Sichot, Rav Menachem Mendel Schneerson, the Lubavitcher Rebbe, expounds that every entity possesses three aspects: First, there is an existential aspect to every entity. Simply stated this means that everything occupies a unique position in space and time, and that unique position is part of the object’s identity. For example, part of Reuven’s identity is that he occupies space not shared by Shim’on, or by anyone else for that matter. The second aspect is the functional aspect. This is the specific and unique function of the entity; e.g., a pen is designed for writing and a knife is designated for cutting. Finally, there are the particulars of the entity. These are minor details not crucial to its overall functioning but that nevertheless contribute to its character and disposition. The color of a baseball bat does not affect its functioning as a bat, but a yellow bat is still not the same as a green one.
In Parashat Terumah, Hashem commands Moshe and Bnei Yisrael regarding the specifics of building and designing the Mishkan. As an entity, the three aforementioned aspects should be present in it as well, best represented by the walls, apparatuses, and coverings. The walls represent the existential aspect, by defining the boundaries of the Mishkan and encompassing everything within. The apparatuses of the Mishkan - the Menorah, Shulchan, Mizbei’ach, etc. – represent the functional dimension, since these items each have their own specific function and purpose, and each contributes to the overall purpose of the Mishkan. The particular aspect manifests primarily in the coverings, and most specifically the outermost layer of multicolored Tachash skins that give the Mishkan an attractive color. This color, while essential to the Mishkan’s identity, is not a functional detail.
The Mishkan resided at the center of the Jewish encampment and was, quite literally, the “heart” of the people. Just as our “heart” had three aspects that precisely defined its identity, so too each of us has his own unique characteristics that define us as what we are. Furthermore, if we are able to distinguish between our functional and particular aspects, while recognizing we each occupy a unique spot in the universe, we will surely be able to improve ourselves and our service of Hashem.