We are charged with the task of revealing the Divine, of bringing God out of His concealment by overcoming the obscuring barriers.
This does not exist in the next world, where the Divine is available according to one's capacity where there is no object of desire, no privilege or duty.
Everything is given and nothing is left to be yearned for.
It is a static non-state in which one performs neither mitzva nor transgression.
The next world is complete and infinitely satisfying.
This world, in contrast, is marked by the need "to do it this day," for only the present strives for perfection.
All of which is only an introduction to Shabbat.
The speculations concerning the nature of the next world are based on the insights of the Sages as well as reasonable hypotheses.
The essence of Shabbat is really a trickle, an infiltration, of the next world into this world.
It is a percolation and diffusion of an existing Divine Reality.
–Rabbi Adin Steinsaltz
From "Hidden Aspects of Shabbat," in The Candle of God by Rabbi Adin Steinsaltz