In order to appreciate Shabbos properly, it is essential to develop an understanding of the idea of 'menucha' that is so central to this holy day. The Torah states: "And on the seventh day, G-d completed the work which He had done, and He rested on the seventh day from all the work that He had done." This passuk poses a difficult problem. It informs us that G-d rested on the seventh day, implying that He did nothing. Yet it also says that on this same day He 'completed' His work of creation, indicating that He did actually create something on Shabbos, and that this final act of creation caused the completion of the world. The Medrash, brought by Rashi, explains that G-d did indeed created something on Shabbos. He created the concept of menucha (rest) through His 'act' of resting. We see from here, that Hashem's menucha did not merely entail an absence of action, rather it involved some kind of active effort. This understanding leads us to ask, what was the active element in Hashem's menucha?
The Beis HaLevi zt"l addresses this question. He begins by explaining the fundamental difference between the first six days and Shabbos. In the first six days, Hashem was actively creating completely new forms of existence from nothing. On Shabbos, He refrained from creating new things, however He did not sit idly, so to speak, and do nothing. What did He do on Shabbos? The Beis HaLevi explains that Hashem is constantly recreating the world. We acknowledge this in birchos krias shema. We say "and in His goodness, He renews the works of creation every day, constantly." This means that Hashem is constantly creating the world anew. If He stopped doing this for one instance then the world would cease to exist. This process began on the first Shabbos of creation, and it is this that is described as Hashem's menucha. It contrasted with the previous six days in that Hashem refrained from creating new things, yesh m'ayin, rather He recreated the world in its previous form. Thus, Hashem's menucha did not constitute a mere refraining of activity, rather it represented a change from creating new things, to recreating them in their previous form. This was the 'creation' of the seventh day.
We are commanded to emulate Hashem's resting on Shabbos by refraining from melacha. However, it is not sufficient to merely do nothing, rather we also must emulate Hashem's menucha. In what way can we do this based upon the Beis HaLevi's explanation of menucha? The Torah tells us that on these six days we must do melacha. This means that we must be involved in creative activity, in this way we emulate Hashem's creation of the first six days. On Shabbos, we must refrain from such activity, however this does not mean that we do nothing. Rather we must emulate the way that Hashem 'rested'. He recreated the world, enabling it to maintain its previous state. In a similar way, on Shabbos, we must actively maintain all the 'creation' of the previous six days, and not let it all go to waste. This means that a significant part of Shabbos menucha is to consolidate one's achievements from the previous six days. In a practical sense, this means that one should go over his previous week, assessing how he grew, and where he faltered. In this way he can prevent the previous week's events from being lost, and he can use them as a springboard for the following week.
Rav Hirsch zt"l points out that this a fundamental aspect of one's avodas Hashem. He learns this out from the Mitzvo of Terumas Hadeshen, the raising up of the ashes, whereby a Kohen must move the ashes from the altar to the ground next to the altar. Rav Hirsch points out that this is the first avoda (service) of the day in the Mishkan, but it is really a continuation of the previous day's avoda. This alludes to us that today's avoda should be a continuation of the previous day's accomplishments. Each day of growth and avodas Hashem should not be contained in a vacuum, isolated from the past. Rather a person must consolidate on this previous accomplishments and build on them in the new day. Shabbos seems to encompass this idea to a greater extent than the other days, because it is the one day when we are free from distractions and are therefore able to step back and assess where we are holding in our avodas Hashem.
Shabbos is the day of rest, however we have seen that the 'rest', involved does not constitute mere inactivity. Rather it require an active effort to contemplate the previous week's accomplishments and failings. May we all merit to attain true Shabbos menucha.