In these parshios of Vayakhel and Pikudei, we have the summation of all of the items that were made for the mishkan, including both the furnishings as well as the garments of the kohanim. The repetition of the items in such detail after they have already been specified in Terumah and Tetzaveh deserves an explanation of its own, but there is another question that is even more bothersome. In Pikudei we have the listing of how much gold, silver, and copper was brought to the mishkan. The Torah itemizes the weight of each material and exactly how much was used for every item, with the amounts balancing out. True, it does show something about the integrity of the enterprise, in that every single bit of gold and silver, etc. that was donated was put to use. But is it really so necessary to itemize every single item and the exact amount of gold that went into it and so on?
While it is true that in the previous parshios of Terumah and Tetzaveh we have the exact measurements of all of these vessels and garments in painstaking detail, those details are significant because they are the halachic requirements of constructing the various items. Some of the items would be used later in the temple and would have to be made in the exact same way if the need arose to make a new one. Even for those items that would later change, there is still great significance in knowing all these measurements because all of these measurements include some sort of religious and mystical significance. The dimensions, the composition, and the way in which they were made reference deep ideas behind them. The itemization in Pikudei, however, seems to be merely an accounting summary: how much gold was brought, how much was used piece by piece and item by item, how much silver was brought etc. Why do we need to have that in the Torah? What is the Torah telling us?
Another noteworthy event reported in Terumah is that it was brought to Moshe Rabbeinu's attention that more than enough material had been collected for the mishkan. Moshe immediately issued a proclamation declaring that Klal Yisroel should henceforth stop bringing more gold etc. It does make sense that they should stop collecting if they don't need it, but from the solemnity of the proclamation, it feels as if there was something inherently wrong with bringing more goods.
There is a pshat attributed to the Ramban [in Emunah uBitachon- assumed to be a talmid of his], regarding the verse, "I adjure you, O daughters of Jerusalem, by the gazelles, and by the hinds of the field, that you not awaken or stir up love until it desires [shetechputz]". The Ramban [or his talmid] explains the passuk in a different sense. He says that the word "techputz" comes from the word "cheifetz" which means "an object". He interprets this verse homiletically as meaning the following: there are, at times, awakenings of deep religious emotions in people; a person is overcome with emotion and feels that "he is connected". Never let those feelings remain as such! It is emptiness unless one turns those feelings into action and concretizes them. Thus, the passuk is describing the profound feelings of love in Shir Hashirim as having to find themselves in deed, never allowing emotion to dissipate into nothingness.
The donations to the mishkan stemmed from an incredible awakening of Klal Yisroel's love for Hashem. There was no clear obligation of how much to give; it was all nidvas halev. Klal Yisroel's religious emotions were at their height. To keep pouring out more and more affection even when it could not turn into something concrete was a travesty. Therefore, Moshe had to stop the collection immediately.
This, then, is what Pikudei is stating. There was an incredible outpouring of Klal Yisroel's love for Hashem, but none of it remained "in the air", dissipating into nothingness. Every bit of this ruchniyus was used to the fullest!