On six days work may be done, but on the seventh day it shall be holy, a day of complete rest to Hashem. (Shemos 35:2)
The flow of this Posuk seems awkward. After the initial statement of “On six days work may be done” one would expect “but the seventh day is a complete rest to Hashem” and after that should come the next statement “the seventh day shall be holy”.
In fact we find in Parshas Ki Sisa, the Torah quoting an almost identical verse in the expected order, “On six days work may be done and on the seventh day there is complete rest, holy unto Hashem” (Shemos 31:15).
Moreover there seems to be another difference between these verses. In Vayekhel it says “whoever does work shall be put to death” while in Ki Sisa it writes “whoever does work shall definitely be put to death”
Shabbos has a positive and negative side to it. We are commanded to rest from work, this is the negative side. However Shabbos does not end there, it is meant to be a productive day, a day when we develop our relationship with the Divine. These two ideas are intertwined and that is why the two statements were said in unison.
Now, there are two possibilities. Either the primary ides is to forbid work on Shabbos, and seeing as we are anyway off work on this holy day we should utilize the opportunity productively i.e. developing our spiritual muscle. Or perhaps the Torah wanted us to have a day of developing our spiritual muscle, and in order to facilitate this development He forbade us to do any work, as mundane activity would be distracting.
The Torah give us the answer. Both options are correct. Shabbos is a holy day because we don’t work. We don’t work on Shabbos because it is holy.
Ki Sisa advances the angle that Shabbos is holy because we don’t work. By ceasing from all productive labour we incalculate within ourselves the knowledge that Hashem created the world. “On six days work may be done and on the seventh day there is complete rest holy unto Hashem” .
The message of Vayakhel, is that we don’t work on Shabbos because it is holy. Shabbos is a day to develop spiritually and for this reason the Torah forbids any mundane pursuits. This is communicated by interjecting “but on the seventh day it shall be holy”, before saying that is “a day of complete rest to Hashem” we are informned that the reason we cannot work on Shabbos is because it is a holy day, a day we devote ourselves to holiness.
Violating the Shabbos of Vayakhel is less severe than violating the Shabbos of Ki Sisa. Vayakehel prohibits work as a means to facilitate growth. Ki Sisa is more direct it prohibits work in order create holiness. Therefore the Torah uses stronger language for working on Ki Sisa.
Shabbos as a day of rest, is designed to be a productive day.