The command to observe the Shabbat is almost always prefaced by the statement, “you shall do your work for six days etc.” Why the need for this prologue related to the regular week? Why doesn’t the Torah just tell us about the actual day of Shabbat?
One possible reason is that the Torah is making clear that it is an obligation to work. Whatever form that work takes it is an obligation for every person to use their talents, abilities, and creativity to help build civilization. By doing so, we become partners with God in Creation. When we observe Shabbat we emulate God by resting from creative activity. Therefore, by engaging in creative activity during the rest of the week we are emulating God’s own creative acts.
Another way of answering our original question is that there needs to be a contrast between Shabbat and the rest of the week in order to make Shabbat stand out and appreciated by us. When we enter Shabbat from a busy work week we experience the spirituality and holiness of Shabbat much differently than if we enter Shabbat from the midst of a vacation. Therefore, by working during the week we are certain to appreciate Shabbat more fully.
There is one final answer that I think sheds a totally unique light on our understanding of Shabbat. Shabbat is not an isolated event in time. Rather, it is the climax of a process representing creation. That process begins on the first day of the week, crescendos in the middle, and climaxes on the seventh day, Shabbat. If Shabbat is part of a process then that process, and therefore Shabbat, is affected by what we do not only on Shabbat but also during the rest of the week. In other words, if Shabbat is 75% of the “process” and the rest of the week is 25%, we cannot reach a 100% level of fulfillment without both parts.
Based on this new understanding it is no longer possible to be a “holy” Jew on the Shabbat while acting dishonestly in business during the week for our weekday improprieties impinge upon our total fulfillment of Shabbat. We can’t just be Jews one day a week. We need to imitate those Manhattan drug stores and be open 24/7 for Torah and Mitzvah observance. By doing so we will attain the wholeness and balance that will enhance our spiritual lives and contribute to our overall fulfillment.