What is “the Testimony”? Rabbi Shmuel ben Rabbi Yishmael said: It is testimony for all who enter the world that there is forgiveness for Israel. Alternatively, it is testimony for the entire world that [Moses] was appointed by the Holy One blessed be He.8The fact that God rested His presence in the Tabernacle was an indication that He had forgiven Israel for the sin of the Golden Calf. Alternatively, it was an indication that He had commanded the construction of the Tabernacle, in contrast to the view of those who thought God would never have issued such a command because a finite space cannot contain the presence of an infinite God (Etz Yosef).
Rabbi Yitzḥak said: To what is this matter comparable? To a king who took a wife and loved her exceedingly. He became angry at her and left her, and her neighbors would say to her: ‘He will never come back to you.’ Sometime later, he sent to her and said: ‘Sweep my palace and make the beds, as on such and such day I will come to you.’
When that day arrived, the king came to her and reconciled with her. He entered the palace [and came] to her, and ate and drank with her. Her neighbors did not believe it. When they smelled the fragrance of perfume, they knew that the king had reconciled with her.
So too, the Holy One blessed be He loved Israel and brought them before Mount Sinai. He gave them the Torah and called them a kingdom of priests, as it is stated: “You will be for Me a kingdom of priests” (Exodus 19:6). Forty days later, they sinned. At that moment, the idolaters said: He will never again be reconciled with them, as it is stated: “They said among the nations: They will not reside here anymore” (Lamentations 4:15).
When Moses went to ask for mercy for them, the Holy One blessed be He immediately forgave them, as it is stated: “The Lord said: “I have forgiven in accordance with your statement” (Numbers 14:20). Moses said: ‘Master of the universe, I am satisfied that You have pardoned Israel, but proclaim before the eyes of all the nations that there is no residual resentment in Your heart against them.’ The Holy One blessed be He said to him: ‘As you live, I will rest My Divine Presence in their midst,’ as it is stated: “They shall craft a Sanctuary for Me [and I will dwell among them]” (Exodus 25:8), ‘and they will recognize that I have pardoned them.’
That is, “the Tabernacle of Testimony,” as it is testimony for Israel that the Holy One blessed be He has pardoned them.