The Chizkuni explains the close proximity between the mention of shemita and Shabbos in this week’s parsha (verses 23:10–13): One might think that during the shemita year—which is called a “year of Shabbos”—one would not be obligated to keep Shabbos. Therefore, the Torah stresses that Shabbos must be observed even during shemita. At first glance, it sounds reasonable to have a break from Shabbos because both shemita and Shabbos are called “Shabbos.” But if we think more carefully, we realize that during shemita we take a break from working in the fields, whereas on Shabbos we cannot accomplish creatively even in areas that have nothing to do with commerce or sustenance. The implication is that on Shabbos it is not enough for business to stop; we have to put our lives on hold. Thus, Shabbos is more all-encompassing than shemita.
One can think of the shemita year as a time when we must surrender our financial stability to Hashem, and this is liable to have a far-reaching—perhaps even irreversible—effect. Imagine: The owner of a spice business has cultivated clientele internationally. If he stops producing spices for a year, not only will he lose his local business, but the international market will look elsewhere for a “responsible” supplier. If that man is shomer shemita and his business collapses, will he consider himself a failure?
Shabbos, on the other hand, demands of us that we spend our time learning and davening, steeped in ruchnius (see Shulchan Aruch סימן ר”צ סעיף ב’ ברמ”א). True, a person may suffer financial loss by being shomer Shabbos, but he feels fulfilled in the sphere of ruchnius, as he has enriched his life on that day. Therefore, even if he were to lose his job, he would not feel that he is a failure for he grew so much on that wonderful day.
True, shemita does not encompass as many areas as Shabbos, yet the danger to self-image may be greater. Nevertheless, a person states: “I am willing to give myself over to the ways of the Torah, and even lose everything, even though I will not see a payoff.” This idea is not found in Shabbos, since on Shabbos we feel enriched by our spirituality.
If this explanation by the Chizkuni is correct, it is not enough to be moser nefesh for the Torah and mitzvos by “being” more spiritual. We even have to be moser nefesh and willing to “lose everything” when we do not see the payoff.