Yerushalayim - The True Simcha of The Whole World

כָל מִי שֶּלֹא רָאָה שִמְׁחַת בֵּית הַשּוֹאֵבָה, לֹא רָאָה שִמְׁחָה מִיָּמָיו (סוכה נא א) Anyone who has never witnessed the Simchas Bais HaSho'eva, has never witnessed true Simcha. You could get Ruach HaKodesh from the tremendous Simcha of the Bais Hamikdash. If a person had to do a math problem, he had to leave Yerushalayim since there is a tinge of sadness when you can’t figure out the problem and Yerushalayim is: מְשׂוֹשׂ כָּל הָאָרֶץ (תהלים מח ג) the joy of the whole world. (Medrash). Chazal say that since the Churban the fruits don’t really taste good the way they used to.

The Gemara in Chagigah (5B) says: אֵין עַצְבוּת לִפְנֵי הַמָּקוֹם there is no sadness by Hashem, since: עֹז וְחֶדְוָה בִּמְקֹמוֹ (דהי"א טז כז) He is total goodness and Simcha. Imagine, we used to say: בֵּית ה' נֵלֵךְ (תהלים קכב א) Let us go to the house of Hashem; i.e., we’re actually going to the house of Hashem, and how much Simcha we had during the שָׁלֹשׁ רְגָלִים three Regalim!

תַּחַת אֲשֶׁר לֹא עָבַדְתָּ אֶת ה' אֱלֹקֶיךָ בְּשִׂמְחָה (כי תבא, כח מז) Not serving Hashem B'simcha is the Shoresh for all Churban.