Rabbi Shimon bar Yochai is considered to possess a spark of Moses’ soul 9see Sefer Hilula D’Rashbi Lag B’Omer pg 30). However, the day of Moses’ death the 7th of Adar is marked as a day of mourning and Lag B’Omer the anniversary of Rabbi Shimon Bar Yochai’s passing is a day of celebration. Rabbi Avraham Yitzchak Sperling ZT’L ZY’A (Sefer Ta’amei Minhagim U’Mikorei HaMinhagim pg.267 paragraph 1) cites a remarkable explanation, Moses was denied entry to the Land of Israel therefore the anniversary of his passing is a time to mourn. Whereas Rabbi Shimon bar Yochai who was endowed with sparks of Moses’ soul passed away in the Land of Israel is an occasion for rejoicing.
Moses’ desire to enter the Land of Israel was to be able to fulfill those Mitzvoth connected to the Land of Israel which only came about generations latter through Moses’ reincarnation as Rabbi Shimon Bar Yochai who dwelled in the Galilee. Recognizing what was denied Moses and ultimately realized by Rabbi Shimon bar Yochai would adequately explain the difference in how the passing of these great men are celebrated.
However how does the passing of Rabbi Shimon bar Yochai fit in to the context of the Sefirat HaOmer period. Rabbi Eliezer Twersky ZT’L ZY’A the Faltishaner Rebbe ZT’L ZY’A offers an insight.
The Omer’s Forty Nine days can be broken up as two groups of thirty two and seventeen days. The first Thirty Two days corresponds to Lev, Heart. The last Seventeen days correspond to the Hebrew word Tov, Good. The implication being, the preparation for receiving the Torah through counting the Omer is to obtain a good heart. (see Avoth 2:10). As a variation on a theme once one has a heart one is prepared to receive the light that is wholly good embedded within the Torah. Consequently, the Thirty Third day of the Omer is symbolic of the first day the D-vine light of Torah shines.
Rabbi Twersky demonstrates from several sources that Rabbi Shimon bar Yochai maintains that an act done without conscious thought is of no effect. While not accepted as definitive throughout the body of Jewish Law it is the accepted opinion concerning the Seven Blessings recited during the wedding ceremony.
Awaking the consciousness to the significance of Mitzvoth in creating harmony throughout creation and therefore the profound importance each person has fulfilling his or her role in observing the Mitzvoth.
Rabbi Shimon Bar Yochai’s Torah epitomized a Judaism of meaning raising observance from mere rote to an experience of dynamic engagement. Rabbi Yaakov Meir Schechter Shlita (V’Katov B’Sefer II, Chapter 10) quotes the introduction of Lekutei Maran that in the Talmud (Shabbat 138b) Rabbi Shimon bar Yochai was the one who asserted unequivocally Torah would never be forgotten among Jewry. Indeed the Zohar III:124b assert that it is through the Zohar Jewry will be taken out of exile. Without overanalysis
By igniting the consciousness to the intense spiritual reality of existence to perceive beyond what one’s eyes see to recognize G-D’s presence in all places throughout time as well as how G-D has empowered those entrusted with Torah to effect the harmony G-D designed in His creation.
Rabbi Shimon Torah illuminates the body of Mitzvoth even those concerning damages and planting as not just being practical but deeply spiritual. Rabbi Shimon bar Yochai’s passing occurring on the Thirty Third day of the Omer, the day when tone’s heart is prepared to receive the D-vine light within Torah intensifies the bond between G-D and Israel akin to the bond created between husband and wife in marriage . Therefore instead of the sense of loss felt on the anniversary of one’s death Lag BaOmer is a time to celebrate like a wedding feast.