1. Yom Kippur is “one in a year” — the concept of unity, and therefore, unlike other Yomim Tovim, Yom Kippur is only one day. The service of Jews on Yom Kippur is teshuvah (repentance), the quintessence of which is “the spirit shall return to the G‑d Who gave it.” Even when housed in the corporeal body, the spirit, the soul, is unified with “the G‑d Who gave it.” This is emphasized by the service of Jews on Yom Kippur being on the level of “one” in the soul — the level of the soul which is called Yechidah. For although Jews are “one nation in the land” the entire year, on Yom Kippur they have the special service of “the spirit shall return to the G‑d Who gave it.”

The unity of Yom Kippur is also expressed in the unity of Jews between themselves. It is a Halachah that on the eve of Yom Kippur each person must appease and beg forgiveness from those whom he has wronged, “so that the hearts of all Jews should be complete one with the other.” Unity is also expressed in bodily functions, eating and drinking etc., for on Erev Yom Kippur it is customary to eat enough for two days. And it is explained in Kabbalah that this is considered as one eating, substituting for the eating that is not done on Yom Kippur. For those things which are relevant to Yom Kippur itself, but cannot be done then, are performed on Erev Yom Kippur. Hence we see that Yom Kippur emphasizes heavily the concept of unity — between G‑d and Jews, between Jew and Jew, and extending even to bodily matters.

Furthermore, the mishnah states: “There were no Yomim Tovim for Yisroel comparable to Yom Kippur.” For it states “On the day of His wedding” — this refers to Mattan Torah, which is Yom Kippur, the day on which the second Tablets were given.” Indeed, Yom Kippur (when the second tablets were given) is superior to Shavuos (when the Ten Commandments were said), for Mattan Torah on Shavuos is associated with the service of tzaddikim (the perfectly righteous), whereas Mattan Torah on Yom Kippur (when the second tablets were given) is associated with the superior service of baalei teshuvah (repentors). As a preparation to Mattan Torah (on Shavuos) the “Jews encamped there opposite the mountain — as one person with one heart.” It was this unity which caused the Torah to be given. On Yom Kippur then (which is superior to Shavuos), the concept of unity must be emphasized even more than Shavuos; and as a preparation to Yom Kippur, also on Erev Yom Kippur.

2. Recently, in connection with the idea of unity between Jews, we have talked of the greatness in having a Sefer Torah written for Jews, through each one buying a letter in it. For besides thus fulfilling the commandment of “Write for yourselves this Song (which refers to writing a Sefer Torah),” it also effects the unity of Jews in a true everlasting union — since they are being united through “the one Torah,” which is true and eternal. The 600,000 letters in a Sefer Torah correspond to the 600,000 general souls, which encompass all individual souls. Hence, the writing of a Sefer Torah encompasses every Jewish soul, of every level and in all generations.

Therefore, those who have not as yet participated in the writing of this Sefer Torah, should, still on Erev Yom Kippur, endeavor to purchase a letter for themselves, their family, and their associates. Since “one may do something to benefit a person even without his knowledge,” people may buy a letter in the Sefer Torah for their friends who are unaware of this project or cannot for some reason do so themselves.

Tanya, in explaining the greatness of giving tzedakah, says that since “with the money (one gives to tzedakah) one could have bought (things) to sustain the life of his own soul,” then when he gives it instead to tzedakah, “he is giving the life of his soul to G‑d.” Hence, when one gives money for a letter on behalf of his friend, this giving of “the life of his soul” expresses the idea of “love your fellow as yourself.”

Through benefiting many Jews with a letter in the Sefer Torah, one unites them with all Jewry — ”Love your fellow as yourself.” G‑d is also called “your Fellow,” as our Sages have said: “Your Friend and the Friend of your fathers, do not forsake — this refers to G‑d.” Hence, unity between G‑d and Jews is thus also achieved when one performs the mitzvah of “Love your fellow (friend) as yourself” by buying letters for others.

Through our service on Erev Yom Kippur (especially regarding the unity of Jews, as above), we effect G‑d’s blessings on Yom Kippur, that all Jews should be written and sealed for good. This blessing comes from the Essence of the Infinite, the epitome of Unity, and includes within itself all particulars. Hence, the blessing thus elicited is also a general one that includes all particular blessings; and is expressed concretely and openly in having children, life and ample sustenance. And it includes the main blessing of the true and complete redemption by our righteous Moshiach, when G‑d’s unity will be openly revealed, as stated: “On that day the L‑rd will be One and His Name One.”

In conclusion. All who have as yet not participated in the writing of the Sefer Torah should buy a letter on Erev Yom Kippur. In addition, to benefit other Jews so that they too shall have a letter in the Sefer Torah. This should be publicized everywhere, and an announcement about it made after the morning and afternoon prayers. This will be the fit preparation to the “one in a year” (Yom Kippur), since every Jew will have a letter in the “one Torah.” Especially when this is done for oneself and others from the level of Yechidah in the soul, the inner core of truth.

May it be G‑d’s will that through doing this with joy and a good heart, going beyond all limits, we will merit the true and complete redemption beyond all limits — “immediately they will be redeemed.” The redemption will be through our righteous Moshiach who will gather together and unite all Jews — “a great congregation will come there” (completeness of the people”) — to the Holy Land, the chosen and unique land (“completeness of the land”), together with the complete Torah, speedily in our days. Then we will merit to see the fulfillment of the promise “all your males shall appear before the Master, L‑rd, G‑d of Yisroel,” and as in the Year of Hakhel, when “the men, the women and the infants” were all included.

The Alter Rebbe taught that Ahavas Yisroel is the conduit for the love of G‑d to the Jews. It states “I love you says the L‑rd,” and the unity between Jews produces this love, expressed in open, revealed good, beginning with the true and complete redemption, in joy and a good heart.