Teshuvah, repentance, is generally divided into two levels, “lower-level teshuvah,teshuvah tataah, and “higher-level teshuvah,” teshuvah ilaah. Chassidus explains1 that the spiritual service and teshuvah of the Aseres Yemei Teshuvah, the Ten Days of Repentance, is that of teshuvah ilaah.

Accordingly, since Yom Kippuris the conclusion and culmination of the Aseres Yemei Teshuvah, “the time for and the days of teshuvah,”2 it follows that Yom Kippur expresses the ultimate level and most complete state of teshuvah ilaah.

This exalted state of teshuvah is also alluded to in Scripture, when the verse states, “For on that day, atonement will be granted you.”3 The verse does not state that HaShem or Elokim — or any of the other Divine Names — grants the atonement, but simply that “atonement will be granted you.” This is because the atonement achieved on Yom Kippur, the loftiest form of teshuvah ilaah, reaches and extends to G‑d’s very Essence, and at that level He transcends all Names and possible descriptions.4

Generally, teshuvah ilaah alludes to a Jew’s cleaving and uniting with G‑d — “Israel and the Blessed Holy One are truly One.”5 This element finds its greatest degree of expression on Yom Kippur — the “one day in the year”6 whose uniqueness lies in the fact that during this day the Jew serves G‑d with his soul’s essence of yechidah,7 the “one yechidah that affirms His oneness.”8

Since teshuvah ilaah is bound up and connected with the absolute unity of the Jew and G‑d Himself, it follows that such an exalted and privileged level of service is to be performed with great joy — joy at having merited to perform this manner of Divine service.9

Specifically, the theme of teshuvah ilaah finds expression in the unity that is expressed through Torah study,10 which utterly binds the Jew with G‑d.11 Torah is expressly to be studied with joy, as it is written, “G‑d’s laws are upright, they gladden the heart.”12

More particularly, the Torah aspect of teshuvah ilaah of Yom Kippur is related to the second set of Tablets, the Luchos Shniyos, that were given on Yom Kippur,13 and which symbolize the element and quality of repentance. For it was at that time that G‑d told Moshe, “I have forgiven [the Jewish people], as you have requested14 — ‘wholeheartedly.’”15

Since a Jew manifests on Yom Kippur such an exalted state of teshuvah ilaah, it is self-understood that G‑d then provides him with what He deems to be all his material and spiritual needs, thus enabling the Jew to be tremendously joyous.

Accordingly, we must understand why we fast and otherwise physically deprive ourselves on Yom Kippur. Isn’t fasting and self-deprivation the very opposite of having all our needs provided for?

In fact, the teshuvah of Yom Kippur, the bonds achieved between the Jew and G‑d through his teshuvah ilaah on that day, is so profound that it transcends “higher” and “lower,” physical and spiritual. It therefore permeates all aspects of the person’s being, up to and including his physical body.

Remarkably, this extraordinary state is achieved specifically through the fasting and seeming deprivation of Yom Kippur, for the sanctity of the Jew on Yom Kippur is such that on this day the Jew derives his very physical and spiritual nurture through his fast.

Thus the verse states, “He vitalizes them through hunger,”16 which is to say that there are levels — similar to the World to Come, where “there is no eating and drinking”17 — where one’s very vitality and nurture, spiritual as well as physical, is derived from the “hunger” itself.

As opposed to other days of the year, the life-force that is provided to keep body and soul together on Yom Kippur derives from the body itself, similar to the Time to Come, when the soul will derive its nurture from the body.18

Physiologically, this is not all that difficult to grasp, for medically as well, when a person is fasting, the body — which constantly requires nurture — does not derive its nourishment then from food but from the energy previously stored within the body itself.

Indeed, on Yom Kippur we readily see how the teshuvah ilaah of that day so impacts the person that his body itself serves as the source of vitality for both body and soul.

Thus rather than existing in a state of deprivation, on Yom Kippur the Jew attains a truly complete state, where food ceases to be a necessity on that day. Understandably, since all his needs are then met even without the need for food and drink, the person is able to possess the degree of great joy required for the lofty level of teshuvah ilaah.

And all of this serves as a precursor to G‑d’s bountiful blessing of the full and complete Redemption, at which time man will be in his most complete state. Moreover, this lofty state is achieved even as man finds himself within this physical world.

Based on Sefer HaSichos 5750, Vol. I, pp. 27-31.