People work in physical and in spiritual ways to repair the reality of the world and this may be considered the meaning of the weekday.
Included in this is the "plowing and sowing and harvesting" of a man's labor on himself.
But, on the seventh day, there is a cessation of all work and a heavenly delight is manifested.
The week is thus devoted to an awakening process from below.
It is as though the Shabbat is the hidden purpose of labor–a purpose that refuses to be revealed except on the seventh day.
As it is written: "And it shall come to pass that every new moon and every Shabbat, shall all flesh come to bow down before Me" (Isaiah 66:23).
The cycle that becomes apparent, therefore, is the intrusion of the Heavenly world into what we like to think of as the rights and habits of the world below.
How else to explain the fact that the stirring of delight takes place by the month or the week, and the souls of men receive their portion at fixed times.
The Book of Bahir has a description of a pillar (or tower) on which souls ascend to Paradise every Shabbat.
And this is possible because only on that day is the higher delight made manifest and the way opened.
On the other days of the week, work has to be done to prepare for this manifestation, which, although it comes with its own regularity, requires an amount of labor that is somehow in proportion to the delight given.
Just as the food enjoyed on Shabbat has to be cooked beforehand, it does not just appear out of the sky, Shabbat is the time for enjoying what was prepared during the week.
The awakening of delight is the result of the performance of mitzvot during the previous days.
The Shabbat is not a free gift.
–Rabbi Adin Steinsaltz
From "Hidden Aspects of Shabbat" in The Candle of God by Rabbi Adin Steinsaltz