"On the first day you must take for yourself a fruit of the citron tree, an opened palm frond, myrtle branches and willows of the brook and you shall rejoice before G-d for seven days" (23:40). While there is also a mitzvah to rejoice on pesach and shavuot it is the holiday of sukkoth that is known as zman simchatenu, the time of our rejoicing. The obligation to rejoice while applicable is not even mentioned regarding pesach . Instead it is mentioned twice regarding sukkot. The Rambam teaches that while all holidays require joy, sukkot carries simcha yetira - extra joy. And it is the holiday of sukkot that is referred to as "chag", the holiday par excellence. What is it about sukkot that brings extra joy?
The mitzvah of simcha , rejoicing on our holidays, consists of three components. Eating and drinking, learning Torah and sharing with others. Man being a physical specimen seeks pleasure. This is legitimate and even mandatory provided it is done in the proper context. Man can not be truly happy if his basic needs are not met. But physical pleasure itself can never bring true and complete happiness. Man's insatiable appetite means that whatever he has he wants more. "Whoever has a hundred wants two hundred" is the tragic fate of man controlled by his physical needs.
Simcha requires Torah learning, spiritual nourishment and intellectual development. The joy of seeking and searching for G-d, of sweat and tears, of exercising our brain is the second level of simcha . "The commandments of G-d gladden the heart" precluding a mourner from participating in this most joyous of activities, the study of Torah.
There is however an even greater level of simcha, that of helping and sharing with others. This is why Judaism claims that a single person can not attain complete joy, deprived of the opportunity of a constant partner. "You shall rejoice on your festival along with your son and daughter your male and female servant, the Levi, stranger, orphan and widow" (Devarim 16:14). The Torah's definition of Simcha requires the participation of others, especially the less fortunate of society. Thus there is a special obligation to give tzedakah at holiday time - feasting while others are in need, is in the words of the Rambam the "joy of his stomach" as opposed to simcha shel mitzvah , religious joy (Laws of Yom Tov 6:18).
The holiday of pesach embodies the concept of physical simcha - we were freed from physical bondage and celebrate with the most elaborate meal of the year. Chametz and matza are the central themes of the holiday. Shavout the day we received the Torah is the celebration of our spiritual simcha . And Sukkoth when we thank G-d for our material blessings is the holiday celebrating Jewish unity and sharing.
Our Sages have emphasized that the four species represent four different models of Jews, ranging from the most pious to the completely unaffiliated. Yet all must come together in order for any to be valid. It is only when we learn that all Jews are a unified whole will we merit the blessing of uphrosh aleinu sukkat shelomecha of being covered with the tabernacle of peace.
Simcha ultimately means being in the presence of G-d. "And you shall rejoice before G-d". The joy of feeling near to the Creator, while difficult to achieve, is an unparalleled one. Sukkot comes on the heels of the aseret yemei teshuva. Yom Kippur, the day of complete spirituality, of closeness to G-d, is the catalyst leading us to zman simchatenu , to rejoicing with our fellow Jew and even non-Jew. Our joy is such that we bring 70 bullocks representing the 70 nations that formed the basis of civilization.
The Shulach aruch , the standard code of Jewish law begins his first section Orach chaim by telling us that we must place G-d before us always. It ends by stating a "good heart is always rejoicing". If we can learn to place G-d before us we are assured of a life of deep happiness. Chag Sameach.