What is the significance of "Orah v'Simchah v'Sason vi'Kar"?
Torah Temimah citing Megilah 16b: Orah is Torah; Simchah is Yom Tov; Sason is circumcision; Yekar (honor) is Tefilin - "All nations of the land will see that Hashem's name is called upon you" refers to Tefilin on the head. Vilna Gaon - Yisrael constantly need two Osos (signs) - Milah and Tefilin. Torah is the intermediary. Shabbos itself is an Os. 'Yom Tov' corresponds to the Os of Shabbos. Torah is included in all of them; the Gematriya of the initial letter of Orah, Simchah, Sason and Yekar is 611, like that of Torah. The entire word is included in the initials. Simchah is going happily to find something; Sason is after it is in his hand 1 .
Malbim: Also the Amim in Shushan had Simchah (15). The Jews had doubled Simchah, open Sason and great honor.
Vilna Gaon: "Sason v'Simchah Yasigu" (Yeshayah 35:10) applies to the future; after attaining Sason, they will go to attain more Simchah. This resolves the 'dispute' between Simchah and Sason (Sukah 48b); both sides there are Emes.