The portion of Va’Yakhel, details the construction of the mishkan. Interesting however is the positioning of the commandment to observe the Shabbat at the beginning of the chapter which is seemingly a non- sequitur. If the portion starts with a theme, it would seem logical that there would be follow thru. However, verse four shifts rather abruptly to the preparatory work for the construction of the mishkan.
Shabbat is mentioned in Torah in two fashions: as an ideal and as a practical means of living with consequences if not observed according to the law. As an ideal, Shabbat is intended as the capstone for God “completing” the creation. God didn’t need to rest, but presented to mankind the idea that one day a week man ought to rest from the burdens and drudgery of survival. One day a week man needed to focus on something other than physical survival. The other context by which Shabbat is referenced is when it is positioned next to the construction of the mishkan with dire warnings. Here it isn’t an ideal, but a practical and ordered means by which to live and be governed by rules.
The kinds of work not permitted on Shabbat are the kinds of work related activities carried on in the building of the mishkan. The thirty nine principle forms of work are so derived. Carrying a heavy burden on one’s shoulder wasn’t one of the works prohibited on the Shabbat because it wasn’t one of the thirty nine principle forms of work. Does that mean therefore that one should be able to bear heavy back breaking burdens on Shabbat? Technically yes, but that would then contradict the ideal of the Shabbat which was introduced at he conclusion of the creation story. According to that concept, man should be able to rest one day a week and turn his mind to other things than physical survival.
The halachic definition of work doesn’t consider the effort involved. In other words, work isn’t defined by the physical energy invested rather by the intention, what is referred to in the Talmud as “melechet machshevet”. Melechet machshevet is concerned not with the process but with the end result. For example, winnowing on Shabbat is forbidden because it involves sifting or separating. The process of winnowing has two stages: Tossing the grain in the air and having the wind blow away the chaff. In and of itself, the tossing of the grain in the wind isn’t forbidden, but since the intent is to have the wind blow the chaff away it becomes forbidden.
Twenty first century technology makes much of our work effortless. One might therefore conclude that when considering the “ideal of resting on Shabbat” as introduced at the conclusion of the creation story it wouldn’t be in violation since it is effortlessly performed. However, the key to determining this would be whether or not what one intends falls under the rubric of melechet machshevet – the intention and final outcome. If the final outcome results in one of the 39 categories of “work” as performed in the building of the mishkan it would be forbidden - even if no physical effort was involved.