Lag BaOmer ל״ג בעומר
The thirty-third day of the count: the mourning of the seven weeks breaks for one day, and at Meron bonfires are lit at the grave of Rabbi Shimon bar Yochai.
The Talmud says the disciples of Rabbi Akiva died "from Passover to Atzeret." The Geonim add: they ceased to die in the middle of the count. Hence a day on which part of the mourning customs is lifted—the thirty-third, "lag" by the numerical value of the letters.
The second explanation is later and bound to Rabbi Shimon bar Yochai: the day is called the day of his passing and "the rejoicing of Rabbi Shimon." Neither the Talmud nor the midrashim say this; the day is first named in the Rishonim, and the pilgrimage to Meron becomes crowded in the age of the Safed kabbalists, under Rabbi Isaac Luria.
We give both reasons and do not mix them: the ceasing of the plague comes from the Talmud and the Geonim; Meron and the bonfires are a custom that took shape much later.
On the timeline
Sources
Chazal: Mishnah, Talmud, midrash, Zohar
- Yevamot 62b — «from Passover to Atzeret»
Rishonim
- Responsa of the Geonim — the plague ceased in the middle of the count
- Meiri on Yevamot 62b — the thirty-third day as the boundary of mourning
Acharonim and later rabbinic literature
- Pri Etz Chaim, Shaar HaSefirah — Meron and the customs of the Safed kabbalists
Basis: Talmud and midrash.