What is the “testimony” to which the Torah refers when calling the Mishkan “The Mishkan of the Testimony”? Rashi explains that the Divine Presence resting in the Mishkan was itself the testimony: “It served as testimony for the Jewish people that G-d forgave them for the incident of the Calf, as He caused His Shechinah to rest among them [in the Mishkan].”
A testimony makes known that which is otherwise unknown or hidden. Facts that are obvious and widely known do not require testimony; in Jewish law, even facts that are currently indefinite but will inevitably become known in the future do not need to be proven with testimony.
Accordingly, inherent in the name “The Mishkan of the Testimony” are the two novelties to which the G-dly revelation in the Mishkan bore testimony.
First: the revelation was in a material structure, built by human effort. A revelation of G-dliness is not entirely novel or unexpected in a spiritual context. A revelation of the Divine within physicality, however, constitutes a “testimony” to a truth that is otherwise existentially hidden in this context.
In addition, the Torah calls the G-dly revelation in the Mishkan a “testimony” because it was an exposé of the essentially unknown. Namely, the Mishkan served as the dwelling place for the essence of G-d that transcends revelation and is not manifest in any G-dly revelation or Divine influx found even in the spiritual realms.
—Likkutei Sichos, vol. 1, pp. 198–199
