As sincere and noble as a person's intentions may be, if he even wants to build a sanctuary for the Almighty G-d, he may not create it on the holy Day of Rest. As long as a person is mortal, he is liable to shortcomings, and holiness does not tolerate imperfection. Only creative acts that are necessary for the service in the sanctuary, the sacrifices and offerings that cannot be brought at any other time, may be done on the holy Sabbath. These actions, albeit human, since they are done in direct service of Hashem are bolstered by Heavenly assistance and thereby become worthy of the state of perfection particular to the Seventh Day. Our eternal life will be based on these actions we perform in the present; every act, small or large, must be appropriate to the person doing it and to the surroundings in which it is done.
Shabbos is not the only Link to the Infinite which is sensitive to the spiritual level of its adherents. Every variation in holiness calls for a change in the form of worship befitting that individual or group, in its striving to cleave to the Eternal. Although there are higher and higher levels of perfection, acquiring any one level partially is no perfection at all. On the other hand, aspiring to levels of transcendence that cannot be achieved is futile. Each person must therefore strive for a level of eternity that is applicable to him in particular. This is seen by the fact that the Tabernacle that should have been built before the golden calf was not the same as the one needed after the golden calf. Although its structure was identical, there was one major difference: for the former any generous person could donate; for the latter only the holy nation could make a contribution. Since the mixed multitude of gentiles that came with them from Egypt to attach themselves to holiness had instigated the first and gravest sin the Jewish People ever participated in, they were no longer deemed worthy of the Divinity that was to dwell in their midst. Thus, the second recounting of the building of the Tabernacle was completely independent of the first. For the status of the nation needed to be reassessed, and a new 'prescription' had to be written for their current level of achievement.
Even when the construction of the Tabernacle actually began, with each person contributing his utmost mental and physical talents, their desire exceeded their ability to achieve, and the people donated more than the work required. Each wise craftsman realized that he had more material than needed and faithfully came to consult Moshe Rabbeinu what to do. As a rule excess is negative, and this was no exception: Moshe thereby ordered the People to stop contributing more than was necessary, as achieving more than prescribed is not achievement at all.
The third itemization of the Tabernacle which the Torah mentions, describes the stages of its assembly. This time, however, it is not to tell us how it was made: instead, it is a description of Moshe Rabbeinu's life-task. As his task was to take all the individuals and make them into a nation; so too, was he the one to assemble the individual parts of the Tabernacle and make them into a worthy edifice. The fact that this structure is identical to the building that the Nation was working on is only because his personal destiny was so intertwined with that of the nation as a whole. Understandably, he was later the one called upon by Hashem to be the first human to enter it.
May we all achieve the utmost pinnacle of success we are truly worthy of.
Adapted from Rabbi Vali's book on Shemos. Questions and subscriptions can be mailed to: the Yeshiva