Aaron the first High Priest, brother of Moses and Miriam, passed away at age 123 on the 1st of Av of the year 2487 from creation (1274 BCE). This is the only yahrzeit (date of passing) explicitly mentioned in the Torah (Numbers 33:38).
Links:
A Midrashic description
of Aaron's passing
More about Aaron
"Aaron" and "On the Essence of Circumstance" -- a spiritual profile based on the Lubavitcher Rebbe's talks
Following their long journey from Babylon (see Jewish history for the 12th of Nissan), Ezra and his entourage arrived in the land of Israel to be near the newly built second Holy Temple in Jerusalem. A relatively small group came together with Ezra, the majority of Jews, including great Torah scholars, choosing to remain in Babylon due to the harsh conditions that were then prevailing in Israel.
Link: Ezra the Scribe
Today is Rosh Chodesh--"Head of the Month"--for the Hebrew month of "Av" (also called "Menachem Av").
Special portions are added to the daily prayers: Hallel (Psalms 113-118) is recited -- in its "partial" form -- following the Shacharit morning prayer, and the Yaaleh V'yavo prayer is added to the Amidah and to Grace After Meals; the additional Musaf prayer is said (when Rosh Chodesh is Shabbat, special additions are made to the Shabbat Musaf). Tachnun (confession of sins) and similar prayers are omitted.
Many have the custom to mark Rosh Chodesh with a festive meal and reduced work activity. The latter custom is prevalent amongst women, who have a special affinity with Rosh Chodesh -- the month being the feminine aspect of the Jewish Calendar.
Links: The 29th Day; The Lunar Files
"When Av begins, we diminish [our] rejoicing" (Talmud, Taanit 26b).
On the 1st of Av, "The Three Weeks" mourning period over the destruction of the Holy Temple--which began 13 days earlier on Tammuz 17--enters an intensified stage. During "The Nine Days" from Av 1st to the Ninth of Av, a heightened degree of mourning is observed, including abstention from meat and wine, music, bathing for pleasure, and other joyous and enjoyable activities. (The particular mourning customs vary from community to community, so consult a competent Halachic authority for details).
Consumption of meat and wine is permitted on Shabbat, or at a Seudat Mitzvah (obligatory festive meal celebrating the fulfillment of a mitzvah) such as a Bris (circumcision), or a "Siyum" celebrating the completion of a course of Torah study (i.e., a complete Talmudic tractate). The Lubavitcher Rebbe initiated the custom of conducting or participating in a Siyum on each of the Nine Days (even if one does not avail oneself of the dispensation to eat meat).
Citing the verse (Isaiah 1:27) "Zion shall be redeemed with mishpat [Torah] and its returnees with Tzedakah," the Rebbe urged that we increase in Torah study (particularly the study of the laws of the Holy Temple) and charity during this period.
The First Temple, why was it destroyed? Because of idolatry, murder and adultery.
The Second Temple, when they were occupied in studying Torah, doing mitzvahs, and acts of loving-kindness, why was it destroyed?
Because there were those who were intolerant of others without cause. Which teaches us that senseless intolerance is equal to idolatry, murder and adultery combined. (Talmud Yoma 9b.)
There is no sin of senseless intolerance listed in Torah. And yet, while the cardinal sins of Torah demanded only 70 years of exile, intolerance is so sinister, so powerful, it can take us almost two thousand years to heal from its wounds.
In simple terms, it’s much easier to deal with obvious, open failures and repair them. Intolerance, however, comes concealed beneath layers of justifications and self-righteousness. When you don’t believe you’ve done anything wrong, and on the contrary, that you were fighting a holy war, it’s hard to make up for all the damage caused.
Yet there is a deeper reason: Other sins, even the most heinous sins, are symptoms of flaws in the human person. To repair those flaws, each of us is granted 70 years upon this earth—ten years for each of the seven categories of emotions.
But intolerance of the other lies at the primal genesis of evil, at the point of fissure and subsequent fragmentation that occurred in the earliest stages of creation, as the universe lost contact with the infinite divine light that preceded it.
Because it is embedded so close to the core of our reality, it can attack the core of the human psyche, chochmah, the seminal point of reason.
That is why its antidote must also transcend reason. It must be related to the primordial infinite light itself, a light that knows no bounds. The key to healing humanity is therefore unreasonable.
Which means that with a single unpredictable and unconditional act of one human caring for another, connecting with another, especially another he feels he cannot tolerate, the whole of creation is healed and fulfilled.