Whenever one wishes to understand the character of a month, the first thing to examine is the holiday schedule of that month. Since each month represents a spiritual force coming into play, that force is most clearly expressed through the days of note that are present in that month.
If we look at the structure of the month of Teves, we note that there are two outstanding aspects. The first is that we have the tail end of the holiday of Chanukah, which straddles the end of Kislev and the beginning of Teves. The month of Teves thus begins with the climax of Chanukah - the seventh and eighth days of the holiday. The final day of Chanukah is referred to as 'Zot Chanukah,' which means, 'This is Chanukah.' This reference indicates that the final day of Chanukah is when we fully recognize the miracle of the oil of the Temple menorah which burned for eight days. It is this culmination of the spiritual influx of the holiday which starts off the month of Teves.
When we look a little further in the month, however, we discover an expression of the exact opposite spiritual energy. Whereas the completion of Chanukah represents the rededication of the Holy Temple of Jerusalem, and a renewed commitment to the Jewish people's relationship with Hashem, the tenth day of Teves is the date that marks the beginning of the downfall of Jerusalem, and the seeming loss of that relationship. This was the day that the city was surrounded and the siege was laid that would ultimately result in the destruction of the second Temple.
It is remarkable that this month contains two significant dates that represent such opposite extremes in the Jewish people's relationship with Hashem.
In order to understand this on a deeper level, we must again recall that all of the structures of time are composed of multiples of six. When we understand this well, we can find parallels between different places where we see this pattern repeating itself. Just as we find that the winter and summer months are series of six, respectively, so are the days of the week a series of six, followed by a seventh, which is Shabbat. Thus, if we look at the day of the week that corresponds to the month of Teves, we can discover something deeper about the character of the month under discussion.
In the series of six which composes the winter months, Teves is the fourth month. It therefore parallels the fourth day of the week, which is Wednesday. If we wish to understand the character of any concept, we must always look for the root of that concept as it appears in the Torah. The Torah is the spiritual blueprint of reality, and thus, we can find the core of any idea in the Torah, most specifically, in the first place where that concept appears.
The first mention we find of a Wednesday in the Torah is the fourth day of creation. The verses in Genesis (1:14-18) describe the creation of the celestial bodies of the Sun and Moon which took place on that day. Significantly, the Torah at first refers to them as 'the two great luminaries.' Subsequently, however, they are referred to as 'the great luminary that rules in the day,' and the 'minor luminary that rules at night.'
The Talmud in tractate Chullin (60b) makes note of the two distinct references to the Sun and Moon. Whereas the first reference seems to equate the two, implying that they were of equal size and importance, the second reference seems to indicate that they were different, the Sun being larger and greater than the Moon.
Rabbi Shimon ben Pazi explains that this seeming contradiction indicates that something was happening beneath the surface on the fourth day of creation. He illustrates it with a homiletical story, which on the surface seems quaint, but actually contains a profound lesson.
He expounds and says that the first reference to 'the two great luminaries' actually implies that the Sun and Moon were originally created of equal size and stature. Upon seeing this, the Moon complained to Hashem, as it were, and said that 'two kings can not use the same crown.' The implication of the Moon's complaint was that there could not be 'two great luminaries,' or two rulers over the heavens, but rather, only one of the two could truly be significant.
Hashem responded to the Moon and said, "Diminish yourself."
The indication was that the Moon was correct in saying that they could not both be significant, and therefore, it was told to diminish itself.
The Moon, however, complained to Hashem, and asked, "Why must I diminish myself if my claim was indeed well founded?"
To this, Hashem responded with a consolation, saying that although it will remain diminished, at least it will appear alongside the Sun in the daytime, at certain points in the month. This would indicate its primacy, as the Sun never appears while the Moon rules at night.
The Moon was not consoled, and asked, "What value is my light during the day, when the Sun shines brightly?"
Hashem again tried to comfort it by saying that it will have its own unique significance, as the Jewish people will count their calendar based on the lunar months.
Again, however, the Moon complained that it is not the sole factor in the calculation of the Jewish calendar, as the lunar calendar is aligned with the solar calendar through the addition of a thirteenth month, seven times every nineteen years. Thus, the Moon does not have absolute significance in this context, as well.
The conversation continued until finally Hashem acknowledged the Moon and said that a special sin offering would be brought on His behalf, as it were, every Rosh Chodesh. This is the first of the month, the very day that the Moon is diminished. This sin offering would atone for Hashem, as it were, for diminishing the Moon.
Like many homiletic stories of the Sages, this story seems fantastic on the surface. On greater investigation, however, it conceals a most profound concept that is embedded into the very fabric of reality at every level.
In order to understand this, we must examine the concept of the Moon and what it represents, and we can then unlock the message of this Talmudic narrative.
When we analyze the nature of the Moon, we find that it is a celestial form that has no light of its own. All of its light is purely a reflection of the Sun's luminance. It is thus no coincidence that the calendar of the Jewish people is based on the cycles of the Moon. It is also not a coincidence that the Jewish people are given the commandment to base their calendar on the Moon at the very moment that they are on the threshold of the Exodus from Egypt, being forged as a nation.
This brings to the fore the fact that just as the Moon has no light of its own and only reflects the light of the Sun, so too, the Jewish people as a nation have no light of their own, as it were, and only reflect the light of Hashem and His Torah. Just as the Moon cycles, sometimes reflecting more, sometimes reflecting less, so too, the Jewish nation also experiences cycles throughout history, sometimes reflecting more of Hashem's light, sometimes reflecting less.
With this understanding, we can see that the conversation that occurred on that first Wednesday of creation between the Moon and Hashem is also a conversation between between the Jewish people and Hashem, concerning their relationship.
The dialogue between the Moon and Hashem took place on the fourth day of the week, and correspondingly, their is a similar exchange that takes place on the fourth month of the year, the month of Teves.
The month begins with the Sun shining on the Moon, so to speak, as we reflect the light of Hashem in the world through the lighting of the Chanukah candles, which serve as a reminder of the miracles He performed for us.
Even though the Jewish people are pleased to be shining Hashem's light into the world by recounting this miracle, there is an implicit complaint, which corresponds to the complaint of the Moon. The objection is that as long as one can see an obvious miracle from Hashem, we are not truly reflecting His light, because the source of the light is too overpowering. When Hashem reveals Himself in the world, it limits our free choice, and thus, instead of our relationship with Him being something we have chosen, there is an aspect of coercion, in a certain sense.
The paradox is that in order for our relationship with Hashem to be completely actualized, there must be a complete eclipse of that relationship. Hashem must hide Himself, as it were, in order to remove the compulsion that exists when His presence is apparent. Only then can we truly choose to enter into a relationship with Him.
In the account quoted earlier from the Talmud, the Moon is instructed to stop reflecting the light of the Sun, to 'diminish itself.' The fast of the tenth of Teves represents the beginning of the destruction of the Temple, and our seeming loss of relationship with Hashem. This precisely corresponds to Hashem's intstruction to the Moon to 'diminish itself,' as both represent an apparent decline in the relationship between the giver (Hashem and the Sun) and the receiver (the Jewish people and the Moon).
Incredibly, at the very moment that the relationship seems lost, when the Jewish people seem to be abandoned by Hashem, heaven forbid, and the destruction of the Temple is imminent, that is the time when they are no longer forced to shine His light, and instead have a chance to choose to reflect His radiance.
This concept is the root of the reason for the exile of the Jewish people into the diaspora, and the possible loss of faith that is the inherent danger as they are dispersed amongst many peoples and many foreign faiths. Although this is a great challenge, ultimately, it paves the way for the possibility for the Jewish people as a nation to actually choose their relationship with Hashem, to choose to reflect His light.
With this idea, we can understand why these two dates are commemorated in Teves, centering around the very middle of the six month series of the winter months. It is in the very depths of darkness that we have the greatest opportunity to choose the light.
Ultimately, we find that the Moon will return to its full state, as we say in the monthly prayer, Kiddush Levana, the sanctifying of the Moon. There we say, "May it be Your will, my Hashem, and the Hashem of my fathers, to fill the diminishment of the Moon, returning it to its unblemished state. May the light of the Moon be like the light of the Sun, and like the light of the seven days of creation, as it was before."
Similarly, in the service of Kiddush Levana, we pray for the day when the Jewish people will be renewed, like the Moon, and they will glorify their Creator, completely reflecting His light. This will occur in the time of the Messiah, which we await each day. That time will be one where each and every human being will choose to reflect the light of Hashem, entering into the most sublime relationship possible with his or her Creator.