What does the Torah mean when it writes "v'Asisa Kol Melachtecha"?
Rashi: When Shabbos arrives, you should consider it as if all your work has been completed. 1
Refer to 20:9:151:1.
So that one can refrain from thinking about one's work on Shabbos.
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
Why does it say "six days you will work"? Is this a Mitzvah?! And what do we include from "Kol", in this verse and in the next?
Divrei Eliyahu, Kol Eliyahu: One who is in the Midbar and does not know which day is Shabbos, every day he does only Melachah needed to stay alive (Shabbos 69b). Remember which day is Shabbos, so you can do all your Melachah in six days, i.e. also what is needed for Shabbos, and on Shabbos you will not need to do any work, i.e. even for Piku'ach Nefesh. The Torah has a hint for everything!