Bar Yochai you girded yourself with strength and waged the war of Torah by the gate, and a sword you removed from its sheath and brought it down against your enemies.
The sword refers to the honed intellect, as is pshat on the gemoro where Beis Shammai runs in with a sword and forces Beis Hillel to sit and agree with their rulings. It’s brought this refers to a battle of the intellect. Through learning Zohar HaKodosh and the aspects of Torah derived through Rebbe Shimon bar Yochai’s teachings, we gain the ability to fight against those things that seek to abnegate the Torah and Jewish religion, as R’ Shimon fought against the Romans. In order to reach understanding of any subject in Torah you must have an intellect sharp as a sword, all the more so in evaluating the value of external things, just like the famous gemoro in Maseches Shabbos with R’ Shimon and the Chachomim discussing the Roman rulers.
In the merit of התנא אלקי רבי שמעון בר יוחאי and the simcha we make today, we should be free from all forms of oppression, we should have sharp minds to probe to the truth of all matters, we should be protected from tumah and false ideologies through our learning, and Moshiach should come swiftly in our own days.