Hundreds of thousands of Jews are in Meron on Thursday night to celebrate Lag Ba'Omer. The holiday marks the passing of Rabbi Shimon Bar Yochai (Rashbi).

The commentary on the Pentateuch called the Zohar (Shining Light), the classical source of Jewish mysticism, is attributed to Rashbi, who lived in the 2nd century C.E, died on Lag B'Omer and is buried in Meron.

The Talmud tells how Rashbi was forced to hide in a cave with his son for twelve years in order to escape the Romans who wanted to kill him for rebellion. During this period, the Talmud relates that a carob tree and spring of fresh water were the pair's only sustenance, and that he and his son reached spiritual heights in Torah study and kabbala that made their return to the everyday world a difficult transition. Rashbi is revered as a mystic, supremely pious sage, who did not engage at all in worldly pursuits.

The night of Lag Ba'Omer, The Boyaner Hassidic Rabbi lights the first flame of the festivities at midnight and the thousands who have come to Meron continue to sing and dance through the night, chanting the refrains of various songs praising Rashbi, expressing the joy of being a Jew, calling on G-d to deliver His people from danger, and describing their confidence that He purifies them from transgressions.

Among them are many three year old boys, brought by their families for their first haircut, called "chalaka", which Hassidim do traditionally in Meron on Lag Ba'Omer.

Israel's first-response group, Magen David Adom (MDA) is at the scene and will be on high alert.

Police in the northern district are in full force to guide traffic in and around Meron.

Preparations are taking place elsewhere in the country as well. While police and paramedics prepare to deal with traffic and respond to injuries, children across Israel are gathering wood for the traditional Lag B'Omer bonfires.

Leading rabbis have called on the public to avoid desecrating the Sabbath in their preparations for the holiday.