Based on a Naaleh.com shiur by Rabbi Michael Taubes
Rav Hai Gaon teaches that the custom to blow shofar at the end of Yom Kippur is based on the Torah obligation to blow shofar on the Yom Kippur of the yovel (the jubilee year). The Kol Bo says it is meant to confound the Satan. The Meiri concurs with this second reason but the Shibolei Haleket, the Mordechai, and the Tur mention the first reason. Tosfot in Shabbat offers a third explanation. The shofar blowing proclaims that night has fallen and that one is now permitted to prepare the festive meal of motzai Yom Kippur. Many rishonim suggest other reasons, among them that it is a sign of the Divine Presence ascending to the heavens.
Why do we blow shofar every year if the shofar of yovel was only blown once in fifty years? In addition, if the shofar was only blown in Eretz Yisrael during yovel, how does it connect to motzai Yom Kippur when the shofar is blown everywhere? Rav Hai Gaon explains that there is a doubt when yovel falls out. Therefore, we blow shofar in every year. This still begs the fundamental question: What is the connection between yovel and Yom Kippur?
The Meshech Chochma discusses the sanctity of yovel and shemitta (the seventh year). While both relate to the land, shemitta is connected to Shabbat while yovel corresponds to Yom Tov. Shemitta and Shabbat both have inherent holiness, while yovel and Yom tov are dependent on the sanctification of the Jewish people. We say in Kiddush of Yom Tov, “Mekadesh Yisrael v’hazmanim.” Likewise, Yovel is established through the proclamation of the Jewish court and its holiness is dependent on our actions.
Yovel signifies repentance and freedom. Property is returned to its original owner, slaves are set free, and liberty is proclaimed throughout the land. While shemitta focuses on the earth, yovel involves the individual. Rashi says the term yovel refers to the blowing of the shofar. Rav Kook explains that yovel is a kind of social and economic revolution necessary for the equilibrium of society. Similarly, the purification of Yom Kippur is the ability to transcend the shackles of the evil inclination. It proclaims freedom from the desires of the yetzer hara. On Yom Kippur, we become like angels divested of physicality. Likewise, yovel has an element of the world to come where the satan cannot rule. ‘Hasatan’ is the numerical value of 364, which signifies the 364 days of the year when the Satan has permission to meddle in our lives. One day in the year, Yom Kippur, we return to our source and are set free of his overpowering influence.
The shofar blast at the end of Yom Kippur heralds the realization of the ideals of yovel. We once again enter the lofty realm of alma d’teshuva (the world of repentance) and alma d’cherut (the world of freedom).