Hebrew Calendar Date: The 18th day of Iyar - the 33rd day of the Counting of the Omer
Torah reference: Lag B’omer is of rabbinical origin
When it began:
The origins of Lag Ba’Omer as a minor festival are unclear. The date is mentioned explicitly for the first time in the 13th century by the Talmudist Meiri. The Talmudic passage states that during the time of Rabbi Akiva in the 2nd century, 24,000 of his students died from a divinely-sent plague during the counting of the Omer. The Talmud goes on to say that this was because they did not show proper respect to one another. Meiri named Lag Ba’Omer as the day the “plague” ended.
After the death of Rabbi Akiva's 24,000 students, he was left with only five students, among them Rabbi Shimon bar Yochai, Rabbi Shimon went on to become the greatest teacher of Torah in his generation, and is purported to have authored the Zohar, a landmark text of Jewish mysticism. Lag B’omer was the day of Rabbi Shimon Bar Yochai's death, a day when he revealed the deepest secrets of Kabbalah and thus was considered a day of celebration.
How it’s observed today:
This association with Rabbi Shimon’s divulging a fountain of deep secrets which brought a great light to the world has spawned several well-known customs and practices on Lag BaOmer, including the lighting of bonfires, pilgrimages to the tomb of Bar Yochai in the northern Israeli town of Meron, and various other customs.
Children play with bows and arrows, reflecting the Midrashic statement that the rainbow (the sign of God's promise to never again destroy the earth with a flood) was not seen during Bar Yochai's lifetime, as his merit protected the world.
Many 3 year old boys get their first haircut on Lag B’omer at the Tomb of Rabbi Shimon Bar Yochai.
Lag Ba’Omer is a popular day for weddings. For those who do not conduct celebrations between Pesach and Lag Ba’Omer, the date often marks the first opportunity for a wedding in the spring or early summer.