1) The significance of the number ten (Yud):
The Hebrew letter Yud (י), which has a numerical value of ten, is unique among the Hebrew letters. Unlike all other Hebrew letters, Yud is a mere point that transcends form and is unaffected by division into particulars. At the same time, Yud represents the essence of a matter that includes all of its forms and details.
Yud is the initial letter of Hashem’s Name and therefore represents Hashem, i.e., the Creator Who is beyond creation. At the same time, Yud represents the spark of holiness (or Neshamah) that emanates from the Creator and animates all existence – down to its finest details.
Yud represents the “Pinteleh Yid” (Etezem HaNeshamah) – the quintessential essence of a Jew. Yet the task of a Jew is to elicit his “Pinteleh Yid” and cause it to permeate all of his various soul powers.
Yud equals ten – representing Redemption by Moshiach (a fact that is reflected in Moshiach’s ten-stringed harp, the tenth red heifer (Parah Adumah) that will then be used, the tenth song of deliverance that will then be sung and so on). True Redemption is accomplished by revealing the indivisible soul or Neshamah that resides within every element of existence (including ourselves), i.e., the G-dly spark (the “Yud”) that animates and pervades all existence.
This, then, is the lesson in divine service that we are to take from the 10th of Shevat: We should reveal the “tenth” within ourselves (i.e., our Neshamah), and by extension, the “tenth” within creation (i.e., its vivifying G-dly force) – and this revelation should permeate our entire being, all of our affairs and every detail of Creation.
2) Significance of the day, month and year:
“Tenth” represents something that is sanctified. This is seen in the verse (Vayikra 27:32), “Any tithe of cattle or of the flock, all that pass under the staff [‘Shavet’ – a word that is practically identical to the name of the month, ‘Shevat’], the tenth one shall be holy to Hashem.”
Further, the Torah there continues (v.33) “...If he shall exchange it (i.e., the animal that was sanctified as a tithe), then both it and its substitute shall be holy to Hashem.” The initials of “he shall exchange it, it shall be” spell Hashem’s Name. Each month corresponds to another combination of the Divine Name and is to be found in another verse in Torah; this passage in particular, includes the specific combination for the month of Shevat.
In addition, the twelve months represent the twelve tribes of Israel. The month of Shevat corresponds to the tribe of Yosef – which is also the Previous Rebbe’s first name [See below, “Significance of the Previous Rebbe’s name”]. Finally, the dual qualities of holiness (the “Yud”) that were discussed earlier, are emphasized in the Hebrew year of his passing – 5710, “Tav Shin Yud.”
3) Leader and “soul” of Jewry:
We can now appreciate how the tenth (Yud) of the month is the most appropriate date for the Yahrtzait – since as a Leader of Jewry, the Previous Rebbe serves as Jewry’s collective soul. On the one hand, he is “removed” and “sanctified” from the rest of Jewry; yet, at the same time, he is the means of eliciting life and all other spiritual and physical needs, to each particular individual.
In addition, the Previous Rebbe greatly amplified the dissemination of Chassidus – bringing its teachings to America, and from there, to the entire world. Chassidus is the “soul” of Torah and it allows the Jew to reveal his soul as well as the “soul” of Creation – thus bringing the Redemption.
4) Significance of the Previous Rebbe’s name:
The Previous Rebbe’s name alludes to these concepts: Firstly, both of his names, “Yosef” and “Yitzchak,” begin with the letter Yud.
In Bereishis (30:24), the Torah tells us the meaning of the name Yosef, “She called him Yosef, saying, ‘Yosef Hashem Li Ben Acher,’ ‘Hashem will add to me another son.’” Chassidus explains that this represents the task of transforming an “Acher” – “another,” i.e., a Jew who, due to his actions, does not resemble a member of Hashem’s nation – into a “Ben,” a “son,” i.e., one who is clearly worthy of being called Hashem’s child. So, “Yosef” means revealing the “Pinteleh Yid” that is buried deep within every Jew (and by extension, revealing the “soul” of the universe).
Earlier in Bereishis (21:3-6), the Torah explains the significance of the second name, “Yitzchak”: “He called his son ...Yitzchak ... all who hear will laugh with joy (Yitzachak) for my sake.”
A Jew can only serve Hashem with true and complete joy when there are no disturbances posed by his bodily aspects and mundane affairs, i.e., when they, too, have been permeated with the spiritual joy of his soul.
5) Three decades of leadership:
The Previous Rebbe’s thirty years of leadership were divided into three periods – each covering another ten years. [Each of these decades called for a unique type of spiritual service. It is explained in many Sichas, that the first decade demanded great self-sacrifice in order to preserve Judaism under Russian Communism; the second decade was characterized by the dissemination of Chassidus in the Poland-Latvia regions; the final decade was focused on the imminent Redemption by Moshiach. To summarize:] The first decade was spent in Russia, the next in Poland and its neighboring countries, and the final ten years were spent in America. Notably, during his final ten years, the Previous Rebbe would specifically sign his second name “Yitzchak” with an enlarged Yud – and that this letter alone was written [not in Hebrew cursive, but] in the Hebrew “Ashuri” script [that is used to write a Sefer Torah].
(Sichas Parshas Shemos 5750)