According to Sephardic tradition, the 33rd day of the Omer is known as the day of the Hillula of Rabbi Shimon Bar Yochai. Hillula means "wedding" which is used here as a euphemism for his departure from this world.
In most communities, and very specially in Moroccan congregations, they light candles to his memory and to the memory of other human-luminaries, like Rabbi Meir ba'al hanes, etc.
Rabbi Shimon Bar Yochai lived and acted mainly during the Second Century of the common era. The collection of Midrashe Halakha Sifre and Mekhilta are attributed mainly to him. He is the fourth-most mentioned Rabbi in the Mishnah.
Rabbi Shimon Bar Yochai and his son rabbi El'azar are held in unique reverence by Kabbalistic tradition, as the author of the Sefer haZohar haKadosh (the Book of splendor).
The Gemara in Masekhet Shabbat 33 tells the extraordinary story of Rabbi Shimon Bar Yochai. He was condemned to death by the Romans because he dared to criticize the Roman government's activities. He escaped to a cave with his son Rabbi El'azar. They stayed there for 12 years. They survived with a spring of water and a carob tree. During those years of isolation they studied Tora and reached an unparalleled level of understanding of Tora and closeness to God.
When the Roman Emperor died and the decree was canceled, they came out of the cave. Soon they perceived that average Jews were not involved in Tora and spiritual matters as they should, instead they were wasting their precious lives in worldly things like work. A celestial voice ordered them back to the cave for 12 months, as a sort of a deprogramming period.
One Friday evening they saw an old man running with two brunches of hadasim (myrtle) in honor of Shabbat. They asked him why two hadasim and not just one? And he said : One for Zakhor, one for Shamor. At that time, Rabbi Shimon told his son: "You see, my son, Jews dearly love Tora and Mitzvot". If they don't spend more time studying, it is not because they don't care. It is just that they must take care of their worldly needs and material obligations.
This thought comforted them and allowed them to see the material world with tolerance and understanding.
by Rabbi Shraga Simmons