The weekday is the time to perform mitzvot whose purpose is to fix what is wrong, break up the hard crust around the heart, and plant the seed.
Such work is done in the upper worlds as well as in the lower and is essential to the preparation for the Shabbat.
It would appear that Shabbat is, therefore, outside the range of positive commandments.
There is nothing to be done.
The Shabbat has another quality, outside of "plowing and sowing" even in spiritual terms of avodah, and not only in terms of physical work.
Its essence is total rest.
–Rabbi Adin Steinsaltz
From “Hidden Aspects of Shabbat” in The Candle of God by Rabbi Adin Steinsaltz