1. A fast, the Rambam says, is “of the ways of repentance (teshuvah). In a time of trouble all should know that evil has befallen them (not by chance, but) because of their wicked deeds.” When Jews will repent, “this will cause the trouble to be lifted from them.” The reason why we fast on specific days is “because of the troubles that happened then, so as to inspire the heart to open to the ways of repentance. It will serve as a reminder of our own evil deeds and those of our ancestors ... which caused them and us these troubles. By remembering these events, we will improve our ways.”

The Alter Rebbe explains that teshuvah is the idea of “the spirit (soul) shall return to the G-d Who gave it.” The soul, whilst in a body, must always strive to be close to and united with G-d. There are several levels of being united with G-d. When a Jew is in a state of perfection, he feels openly that his soul is verily a part of G-d — “the soul that You put in me.” Sometimes, however, he does not feel this, but knows only in a general fashion that G-d created him by giving him his soul. Teshuvah is the idea “the soul shall return to the G-d Who gave it.” Notwithstanding a Jew’s previous spiritual level, the soul returns to “the G-d Who gave it” — he has the highest revelation of G-dliness. On the other hand, even when he is on the highest of levels, he can always go yet higher and closer to G-d — for G-d is infinite.

There is special opportunity for teshuvah on a fast, as emphasized in the Haftorah — “Seek the L-rd while He may be found, call upon Him while He is near.” Not only on a fast day is G-d ready to favorably accept a Jew’s endeavor to come close to Him, but G-d makes Himself “near” and able to be “found” by a Jew.

Moreover, the term “found” indicates that the closeness to G-d achieved on a fast is infinitely greater than the effort invested — just as when a person “finds” something it is without any effort. A Jew need but pick need but pick up the “find” and announce that it is his — that he wants G-d’s revelation. Since “all your people are righteous,” and G-d fulfills the desires of the righteous, G-d fulfills this desire too — and a Jew becomes united with G-d.

This is the greatness of a fast. Although it commemorates a tragic event, it is nevertheless “a descent for the purpose of an ascent” — to arouse Jews to repent. A Jew knows that G-d does not wish to do him harm, and does not punish him just for the sake of punishment — but to arouse him to repentance.

This is why a fast is called “a day desirable to G-d” — for then a Jew’s soul — “a part of G-d above” — is aroused to return to and unite with G-d until they are one: “Israel and G-d (through Torah) are one.” In such a state a Jew can annul the exile (the reason of the fast). As our Sages said: “G-d decrees and the righteous annuls” — and “all your people are righteous.” Furthermore, our Sages say, if one righteous person would do perfect teshuvah, Moshiach would come.

A fast (which is “of the ways of teshuvah”) is obligatory for all Jews, from “the heads of your tribes” to “the drawers of your water.” Even the greatest of Jews who spends all his days in repentance, must, when it is a fast, be on yet a loftier level of teshuvah. On the other hand, the simplest Jew is able to return to G-d and openly be on the level of a “tzaddik” — and bring Moshiach.

Since teshuvah is thus applicable to all Jews, its results are also applicable to all Jews. Teshuvah is regret over the past and good resolutions for the future. Since “deed is primary,” good resolutions must be translated into actual deed. Thus on a fast all Jews must increase in the three things on which the world stands: Torah, prayer and deeds of loving kindness.

Since these three things are equally applicable to all Jews, their fulfillment emphasizes the unity of Jews. Indeed, these things themselves stress the theme of unity. One must pray “as a servant before his Master” — self-nullification and unity with the one G-d. Torah is “one Torah for all of us.” Good deeds, tzedakah, unites the rich and poor. Indeed, “more than what the rich man does for the poor man (by giving tzedakah), the poor man does for the rich.” Not only is the rich giving to the poor, but simultaneously the poor is giving to the rich -unity of Jews.

Through increasing the three things on which the world stands, Jews assure the stability of the world, enabling them to carry out their tasks with strength and peace — preparing for the true and complete redemption.

2. The above applies to all fasts. In addition, today’s fast has a special lesson commensurate with the events it commemorates.

On the 10th of Teves “the king of Babylon surrounded Jerusalem and laid siege to it.” This was the beginning of the destruction of the Bais Hamikdosh and subsequent exile. Because all the other calamities were a result of the siege, the 10th of Teves is a very tragic event. The immensity of it is emphasized by the siege taking place on “the tenth day of the tenth month (10th of Teves). The number “ten” is associated with holiness — “the tenth will be holy.” Thus the tenth day of the tenth month is a time auspicious for a great revelation of holiness. Instead, the siege of Jerusalem started on this day, which was the beginning of the subsequent destruction and exile. That this should happen on such a potentially holy day indicates the severity of the event.

Since “the descent is for the purpose of an ascent,” it follows that this very great descent on the 10th of Teves is for the purpose of a correspondingly great ascent — greater than that which follows other fasts.

Because the 10th of Teves was the beginning of exile, it is the appropriate time to annul the exile — through annulling the cause of the exile: “We were exiled from our land because of our sins.” When the cause is eliminated, the effect immediately follows — “they are immediately redeemed.”

The principal sin that caused the exile was groundless hatred. This will be annulled through increasing in love and unity of Jews. Since G-d always prepares the cure before the illness, we must conclude that in the siege of Jerusalem there is an allusion to its “cure” — the unity of Jews.

Jews were united from the first instant Jerusalem was besieged — for no Jew could leave the city. Thus all the Jews in Jerusalem were united in that they were all in Jerusalem — “the city which makes all Jews friends.” Indeed, the Jews had no choice in the matter. It was Nevuchadnetzar, the mightiest monarch of the world, who, by besieging Jerusalem, succeeded in forcing Jews to be united!

Such unity was of course steeped in Torah. They were together in Jerusalem, which means “perfect fear of heaven,” where the Bais Hamikdosh was situated, sacrifices offered, the kohanim, levi’im, and yisroelim performed their functions, and the Sanhedrin ruled on halachic questions — and the halachah illuminated the daily life of the Jews.

Thus, although the siege was the beginning of the exile, it also contained the “cure” for the exile — unity of Jews. The lesson from this is that every Jew must unite with his fellow, a unity associated with Torah and mitzvos — unity in “Jerusalem,” “perfect fear of heaven.”

This year, the 10th of Teves is the first day after Shabbos parshas Vayigash, and the Haftorah read then emphasizes the unity of Jews. It relates Yechezkel’s prophecy (Yechezkel 37:16-25): “Take one stick and write upon it ‘For Yehudah and for the children of Israel his companions. I And take another stick and write upon it ‘for Yosef, the stick of Ephraim, and for all the house of Israel his companions.’ Join them one to the other to make one stick and they shall become one in your hand.” The prophet then continues to explain the meaning of the sticks: “Thus says the L-rd G-d. I will take the stick of Yosef which is in the hand of Ephraim, and the tribes of Israel his companions, and I will put them together with the stick of Yehudah and make them one stick, and they shall be one in My hand And I will make them one nation in the land and one king shall be for all of them ... and Dovid My servant shall be their ruler forever.”

Although there are 12 tribes, which in general are divided into two — the stick of Yehudah and the children of Israel his companions, and the stick of Yosef in the hand of Ephraim and his companions — G-d says they must be united into one stick. This is the way to bring the future redemption — “Dovid My servant shall be their ruler forever.”

The great necessity for unity is emphasized by the situation in the times of Yechezkel. The capital of Yehudah was Jerusalem. Ephraim and his companions prevented Jews from going to Jerusalem on the festivals. Nevertheless, says Yechezkel, even when Jews are on such a low level, we should unite with them to the extent that Yehudah’s redemption depends on the unity between his stick and Ephraim’s stick. Certainly then, today, when Jews are on a low level only because they know no better — we must certainly try to unite with them by bringing them closer to Torah and mitzvos.

Moreover, this Haftorah is read before the 10th of Teves. This teaches that a Jew has the ability to unite with others of his own free will — “You shall join them to make one stick.” When Jews are united of their own will, through all acting consonant to the “one Torah,” we do not need the “cure” alluded in the siege, when it was a non-Jew (the king of Babylon), who caused their unity.

3. There is an additional lesson to be learned from the first section of parshas Vayechi, which is today’s portion of Chumash. It states: “Ya’akov” lived 17 years in the land of Egypt.” These were the best years of Ya’akov’s life for he had sent Yehudah ahead of him to Egypt to found a Yeshivah. Through Torah study, and following its directives, one’s life becomes worthy of the name: “Ya’akov lived” — even in Egypt.

The lesson from this: When Jews are in exile (Egypt), they must reveal the purpose of it — to make a “yeshivah” there — to unite all Jews through Torah. Then life in exile is a worthy one, and it is the true preparation to the future redemption.

Ya’akov, before he died, commanded Yosef: “Do not bury me in Egypt ... but carry me out of Egypt.” Although a Jew’s life in exile is a worthy one (“He lived”), nevertheless, G-d forbid to think that exile is a Jew’s rightful place. A Jew must constantly cry out — “Carry me out of Egypt!”

Moreover, Ya’akov was not satisfied just with Yosef’s assurance, and made him swear to take him from Egypt. A Jew’s place is not in exile. He requests from G-d — and, so to speak, makes G-d swear — to “carry me out of Egypt.” A Jew desperately wants to leave exile!

And when a Jew conducts himself according to the Torah’s directives, G-d indeed takes him and all Jewry out of exile, and brings them to Eretz Yisroel “on the clouds of Heaven.”