Rabbi Yonasan Sacks
Shabbos and Yom Tov reflect two distinct models of kedusha. Although we are obligated to recite Kiddush each Shabbos, the essence and kedusha of Shabbos is kvia vkayma, set and predetermined. This aspect of Shabbos is evident in the beracha of “mekadesh haShabbos”.
Yom tov, however, reflects a different foray into kedushas hazman. The onset of yom tov, which is generally linked to specific calendar dates, is dependent on the Sanhedrin and Keneses Yisroel who determine Rosh Chodesh. This unique element of yom tov is reflected in the beracha of “mekadesh Yisroel vhazmanim”.
The Meshech Chochma explains that a similar distinction can be made between Shemitah and Yovel. The Toras Kohanim comments, "kshem shene'emar b'Shabbos Bereishis 'Shabbos Lashem', kach ne'emar b'Shevi'is Shabbos Lashem". Shemitah, like Shabbos, posses a fixed kedusha which is not dependent on kedushas beis din. The beginning of the Shemitah year automatically renders fields ownerless and prohibits the farmer from guarding and tending his field. Similarly, the Mordechai explains, that Shevi'is annuls loans, even if the lender fails to declare "meshamet ani boch". The very purpose of Shevi'is, which is to reaffirm "ki li kol ha'aretz", is an essential theme of Shabbos itself.
Yovel, however parallels yom tov. Just as Rosh Chodesh and yom tov require kiddush beis din, so too the Torah emphasizes “v'kidashtem es shnas hachamishim shana.” the very term “lochem” so essential to kiddush hachodesh - “hachodesh hazeh lochem” - is used to describe the essence of Yovel - “kadosh tihiye lochem”. Just as yom tov serves as a zecher l'yetsias Mitzrayim, where we acknowledge our freedom, so too Yovel is a time when all Jewish slaves must be freed.
Both models of kedusha characterize kedushas Eretz Yisroel. On one level, Eretz Yisroel posses an inherent and intrinsic kedusha, independent of Keneses Yisroel. Complete kedushas ha'aretz however, requires the active participation of Bnai Yisroel.
Shemitah and Yovel teach us to recognize, appreciate and create kedusha. May we be worthy of this lofty privilege.