Shabbat is the seventh day of the week in which god rested from creation and in that light he forbade upon the Jewish people to do work on this day.
and this is this is the negative side of shabbat not to do work (shamor).
in addition there is a positive side to add light into the Shabbat to fulfil the positive commandments of Shabbat (zachor) which that is accomplished by lighting Shabbat candles and having the Shabbat meals and reciting the special Shabbat prayers.
if one only rests from work they have accomplished a lot on one part of Shabbat yet they have yet to fulfil the second part, the positive part of Shabbat.
The mitzvah of Shabbat is one of the most important mitzvos, howeveras in all aspects of Judaism the more one fulfils the better it is yet that doesn’t negate the importance of every single mitzvah on its own right.
