The Posuk says "Like Hashem Commanded Moshe"
In the Parsha we find, after each item that Betzalel made it says, he made it exactly the way "Hashem commanded Moshe". Why was it necessary for the Torah to repeat this so many times?
The Bais HaLevi answers, the sin of the Egel was that Klal Yisroel decided to make something to serve as a "go between" - between Hashem and the Jews. Although their motives may have been L'Shem Shamayim, they sinned by not asking Hashem if he agreed to this way of serving him. Their sin was not doing "like Hashem had commanded".
Since the purpose of the Mishkan was to atone for the Egel, they had to make the Mishkan in total compliance with Hashem's command in order for the atonement to be acceptable. Therefore the pasuk tells us after each step of its completion, that it was done exactly the way "Hashem commanded Moshe".