Lag BaOmer isn’t actually mentioned in the Bible at all. It’s a later tradition that grew out of a few different stories and customs tied to the Omer period, which is biblical.

Here’s what’s in the Bible: in Leviticus, there’s a command to count 50 days from Passover to Shavuot — this is called the Counting of the Omer. Each day, a sheaf of grain (an “omer”) was brought as an offering in the ancient Temple.

Now, why do we celebrate specifically the 33rd day (Lag = 33 in Hebrew)? That’s where it gets more historical/traditional than biblical:

• One popular explanation is that a deadly plague that hit Rabbi Akiva’s students ended on that day. That’s not in the Bible — that’s from later rabbinic sources.

• Another tradition says it honors Rabbi Shimon bar Yochai, a 2nd-century sage and mystic who is said to have died on this date. He’s believed to have revealed deep spiritual teachings (like parts of the Zohar, a main text of Kabbalah).

• The bonfires? Those are thought to symbolize the “spiritual light” he brought into the world.

So in short: Lag BaOmer is not a biblical holiday, but it connects to biblical times through the Omer count and has picked up layers of meaning through Jewish history and folklore.