Adapted from an excerpt of a letter by the Rebbe, Rabbi Menachem Mendel Schneerson, of righteous memory, dated the 5th of Tevet, 5736 (1976):

...In reply to your inquiry and request for instructions in connection with the forthcoming Fast of the Tenth of Tevet, in view of the situation in and around the Land of Israel...

I will set forth, at least, several suggestions after the following introductory remarks:

Regrettably, there are people who claim that it is necessary to think and act "big," in terms of global dimensions and stupendous undertakings, etc., etc. Surely they mean well; and to the extent that such resolutions are practical and are actually carried out—they are very helpful to improve the situation.

Yet, we must never overlook – indeed, rather greatly emphasize – the so-called "small and unsophisticated" things which each modest congregation, or even each individual, can and must do—beginning with the old, yet ever-new, Jewish way, collectively as one people and also as individuals. This is the action of hakol kol Yaakov ("the voice is the voice of Jacob") – Torah and prayer – which G‑d Himself has shown us to be the first effective action to nullify the power of yedei Eisov ("the hands of Esau")—in whatever shape or form they are raised against us.

Certainly this should find the fullest expression in a day which the Code of Jewish Law declares to be a Day of Fasting, one to which the prophet Isaiah refers as a "chosen fast... a fast and time favored by G‑d."

Now, in answer to your inquiry, and since the Fast of the Tenth of Tevet is especially connected with the Land of Israel and the Holy City of Jerusalem (recalling the siege of Jerusalem), my suggestion – in addition to the regular "observances" on Fast Days, as set forth at length and in detail in Jewish law and in books of Jewish philosophy and Chassidic teachings – is as follows:

During this day – expressly for the sake of the security and strengthening of the Land of Israel, materially and spiritually, and for the material and spiritual benefit of all Jews wherever they are – in the Land of Israel as well as in the Diaspora – and particularly for the benefit of our brethren behind the "Iron Curtain"—

A special effort should be made in the spirit of traditional Judaism—in the areas of Torah, prayer and charity.

Specifically: After praying (both in the morning and in the afternoon) to learn (and where there already are daily study groups, to add) a subject in Torah, including practical Jewish law.

Immediately following the prayers, even before learning, to say several chapters of Psalms (in addition to the regular daily portion).

Before and after prayers—to give charity (in addition to the regular donation), including charity for a sacred cause or institution in the Land of Israel, the "Land of Living."

Needless to say, one who repeats the above again and again in the course of the day, is to be praised.

And each time—the more one does it (in quantity and quality), is to be praised all the more.

And, as in all matters of holiness, it is desirable that all the above be done in the presence of a congregation.

May G‑d accept, and He will accept, the prayers and supplications of Jews wherever they are, and soon, in our very own days, may the promise be fulfilled that "These days will be transformed into days of rejoicing and gladness," with the true and complete Redemption through our righteous Moshiach.