“And let all among you who are skilled come and make all that the Lord has commanded.”
Parashat Vayakhel opens with Moses assembling the entire Israelite people-men, women, and children-signaling that something important is about to happen. Moses delivers two pithy statements about Shabbat (if you labor on Shabbat you’ll die and don’t make a fire) and then continues with extensive instructions, numbing in detail, for construction of the mishkan, the Tabernacle. The rabbis interpreted this juxtaposition to mean any task required to build the mishkan was considered labor and therefore forbidden on Shabbat.
Working on Shabbat, then, is not a matter of how much you sweat. It’s whether or not the activity is related to one of the 39 tasks requires to build the mishkan. This is one of the reasons the laws of Shabbat are often perplexing. After all, it is hard to understand why digging a hole to plant a flower is forbidden on Shabbat, unless you know that digging a hole was one of the tasks necessary to build the mishkan.
The bigger lesson behind the rabbis’ interpretation is that time trumps space. That is because time, once used, cannot be reclaimed. Shabbat happens only on Shabbat; you cannot “make it up” on Tuesday if you missed it. The mishkan, on the other hand, can be erected anywhere, making that space sacred, but only for the time the mishkan rests there.
Parashat Vayakhel provides a list of what not to do on Shabbat. The question what we should do to honor the sanctity of Shabbat remains open.