Why does the Torah need to tell us to work six days? And how can one finish all one's work in one week?
Rashi: It means that, when Shabbos arrives, we should consider it as if all our work has been completed. 1
R. Bachye (in the name of the Rambam): It means that, during the week, one is able to serve Hashem by means of all one?s mundane occupations. 2
Divrei Eliyahu and Kol Eliyahu: The Gemara in Shabbos 69b rules that, someone who is in the desert and does not know which day is Shabbos is permitted to do as much work as he needs to stay alive - Shabbos included. Consequently, the Torah warns us to remember which day is Shabbos, in order to be able to all our work in six days - also what is needed for Shabbos, and to desist from working on Shabbos. 3 4
Why is Shabbos specifically on the seventh day?
R. Bachye #2: Because it (the weekly cycle) is part of the cycls of nature is placed in between the daily and monthly cycles, and all the issues concerning nature are based on it (the number seven), as are many Mitzvos in the Torah. 3
Seeing as each day of the week corresponds to one of the Sefiros, and Shabbos was the last day of the creation which is why Chazal (in Midrash Rabah) say that Kenesses Yisrael is the partner (the Bashert) of Shabbos.
It is also known as ?Kenesses Yisrael,
See R. Bachye who elaborates and R. Chaval?s footnotes DH ?Hekef Emtza?i? & ?u?MItzvos Rabos ba?Torah?.
What is the difference between 'Avodah' and 'Melachah'?
Ramban: 'Avodah' refers to work that is not for one's immediate benefit, such as work in the fields; 1 whereas 'Melachah' refers to work from which one benefits immediately, such as preparation of food -- both of which the Torah is now coming to forbid on Shabbos. 2
Ramban: See for example, Shemos 1:14, and Bereishis 4:12 .
Though it permits the latter on Yom-Tov.
Having written "Sheishes Yamim Ta'avod," why does the Torah add "v'Asisa Kol Melachtecha?
