Rabbi Isaac Luria Ashkenazi, known as Ari HaKadosh ("The Holy Lion") passed away on the 5th of Av of the year 5332 from creation (1572 CE). Born in Jerusalem in 1534, he spent many years in secluded study near Cairo, Egypt. In 1570 he settled in Safed, where he lived for two years until his passing at age 38. During that brief period, the Ari revolutionized the study of Kabbalah, and came to be universally regarded as one of the most important figures in Jewish mysticism. It was he who proclaimed, "In these times, we are allowed and duty-bound to reveal this wisdom," opening the door to the integration of the teachings of Kabbalah--until then the province of a select few in each generation--into "mainstream" Judaism.
Links:
A Tale of Two Kabbalists
Fallen Sparks
What is Kabbalah?
About The Ari
R. Chaim Ozer Grodzinski served as rabbi of the prestigious Jewish community of Vilna, Lithuania, for over fifty years. He was a distinguished scholar, and he authored Achiezer, a collection of halachic responsa.
A devoted communal activist, R. Chaim Ozer worked together with the fifth and sixth Lubavitcher Rebbes, R. Sholom DovBer and R. Yosef Yitzchak Schneersohn, on many projects to ease the plight of Russian Jewry (such as the 1929 struggle to send matzah into the Soviet Union).
Link: The Rebbe Goes to Vilna
During the “Nine Days" from Av 1st to the Ninth of Av, we mourn the destruction of the Holy Temple. We abstain from meat and wine, music, haircutting, bathing for pleasure, and other joyous (and dangerous) 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 certain mitzvot) such as a brit (circumcision), or a siyum celebrating the completion of a course of Torah study (i.e., a complete Talmudic tractate). The Lubavitcher Rebbe, of righteous memory 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 "Zion shall be redeemed with mishpat [Torah] and its returnees with tzedakah," (Isaiah 1:27) the Rebbe urged that we increase in Torah study (particularly the study of the laws of the Holy Temple) and charity during this period.
Links:
Nine Days laws and customs
Daily live siyum broadcasts
Learn about the Holy Temple in Jerusalem
Naturally, we think of the Jewish people as a conglomerate of many Jews. But the Baal Shem Tov saw the Jewish people as a single, indivisible whole.
Think of a geometrical point. A point is indivisible, but not because it is too hard, too big, or too small to cut up. A point simply has no area to be divided. That’s what makes it a point.
And yet, from a point you can extend infinite lines radiating in infinite dimensions.
In a somewhat similar way, but far beyond, all Jews are one Jew. Which means that in any one Jew, you will find all of us—just from a different angle.
So that whatever happens to any one of us instantaneously happens to the entire Jewish people. Not by some ripple effect or resonance. But because any one sample of the whole is the whole and the whole is one.
And so, the Baal Shem Tov taught, when the light of any one Jewish soul breaks free, the entire nation is redeemed along with it.
And accordingly, the Rebbe wrote, the ultimate exodus of our entire people is also a personal, intimate liberation for every Jew.