I am confused about the fast of the 10th of Tevet. This calendar year it falls on a Friday, which means that we fast all the way up until we make kiddush. I thought we were not allowed to enter Shabbat fasting!


Ordinarily, you are correct—one must not enter Shabbat while fasting. This particular fast is an exception. In fact, according to one opinion,1 if the 10th of Tevet would fall out on Shabbat, we would have to fast the whole Shabbat. This is based on the similarity of the text describing the events of the day2 to the wording in the Torah describing Yom Kippur,3 from which we know that Yom Kippur is never postponed. (Our calendar is set up in such a way that the 10th of Tevet cannot occur on Shabbat, but in times when the calendar is determined by the central court in Jerusalem, it is a possibility.)

What is so exceptional about the 10th of Tevet? Well, it was the day that the Babylonian army led by Nebuchadnezzar laid siege to Jerusalem. Superficially, that seems less significant than the day the walls were breached (for which we fast on the 17th of Tammuz), or the day the Temple was set afire (for which we fast on the 9th of Av).

But that’s only when you look at the tragedy involved. A fast, however, is declared not just so we can demonstrate how sad we are. A fast is called by the prophet4 “an auspicious time”—a time when we are empowered to rectify whatever went wrong on that day.

Now, if you want to fix something, where do you start? If a river is polluted, do you start your cleanup by washing off the beaches downstream, or do you go upstream and plug up the sources that are pouring in all that sewage and toxic waste? Similarly, when we want to correct the past, the most vital part of that correction is to go back to where it all started from, and fix things there. And that’s the 10th of Tevet.

On the 10th of Tevet, as I wrote, the king of Babylon and his troops set siege to Jerusalem. No one could enter and no one could leave. All of Jerusalem’s inhabitants were forced to live with one another, without escape. “G‑d sends the cure before the illness,” our sages say, and this is a prime example: the siege itself provided the Jews within Jerusalem an opportunity to come together as one—and if they had, no army could have attacked them.5 Nebuchadnezzar and his warriors would have retreated to where they came from, as had the army of Sennacherib years before.

Now, an amazing thing: We have been in exile since the destruction of the Second Temple, close to two thousand years. What is the primary, underlying cause of such a long exile? Our sages attribute it to one principal factor: causeless hatred. When there is harmony among Jews, they are invincible. When there is, heaven forbid, discord and acrimony, there is exile. The siege of Jerusalem on the 10th of Tevet, it turns out, provided us an opportunity to fix the root cause of the exile before it had even started.6

Just as it was the first time, so too every year, the 10th of Tevet is an auspicious time for us to reach all the way into the first cause of our exile and to cure it, by creating caring and harmony among Jews, and thereby taking us all out of our exile once and for all. For such an empowerment, we may have to sacrifice some of the enjoyment and tranquility of Shabbat, but it’s certainly worthwhile.

Practically speaking, on this Friday evening, kiddush is made as soon as three medium stars have appeared and the fast is officially over (see here for the exact time at your location). Those fasting should not eat until after hearing kiddush.

Wishing you an easy, meaningful and effective fast.

Rabbi Eliezer Zalmanov for “Ask the Rabbi” @


Based on several talks of the Rebbe. See Likkutei Sichot, vol. 25, p. 267, and volume 30, p. 220.