Komentaryo sa Exodo 31:15: Rashi, Chizkuni, Sforno & Or HaChaim

שבת שבתון denotes, reposeful rest and not rest of a casual character.

ששת ימים יעשה מלאכה, “during six days work may be performed.” This verse refers to work being performed if you so desire; another verse says ששת ימים תעבוד, “during six days you are to perform the kind of work which is normally felt as something burdensome.” (Exodus 35,2) The reason why the Torah writes both formulations is to tell us that when we observe the Torah, others may perform this kind of labour on our behalf; if we do not observe the Torah, such as “benefiting” by an extra day of work, we will experience all seven days as days when we have to perform demeaning work. The repetition of the instruction was necessary on account of the penalty of מות ימות, “he will be executed,” having been written twice.

ששת ימים יעשה מלאכה, during the six days of the week which correspond to the days when G’d created the universe you can busy yourselves with working on the construction of the Tabernacle. There is no good reason why this project should override the commandments governing the Sabbath. The only time a commandment overrides such commandments is when the Torah linked the commandment which would override it to a specific time frame, such as the circumcision of a baby on the eighth day after its birth, or the type of sacrificial service in the Tabernacle of which the Torah said that it must be performed every day i.e. including on the Sabbath. Any other commandment that is capable of being performed on a day other than the Sabbath does not override the Sabbath.

‘קדש לה HOLINESS TO THE LORD — The observance of its holiness shall be (it shall be kept holy) to the glory of My Name and by My command (because I have commanded it).