One of the many lessons of Sukkot is that it reminds us of the importance of Jewish unity. The Torah tells us, “You shall rejoice in your feast; you and your son and your daughter and your man-servant and your maid-servant and the Levi and the stranger and the orphan and the widow that are within your gates…” emphasizing the concept of unity.
According to the Torah, true rejoicing can only be achieved when we are united and include those less fortunate in our good fortune, as emphasized in the Torah, “your man-servant, maid-servant, the Levi, the stranger (convert), the orphan and the widow.”
But Levites and converts to Judaism (the stranger) are not less fortunate than most of us.
This teaches us that Jewish unity means including those Jews who are different i.e. Jews by inheritance and Jews by choice, as well as Jews who are more religious (Levites do more mitsvot) or less religious (maid-servants do less mitsvot) than we (ordinary Jews) are.
The Sukkot holiday teaches us the importance of Jewish unity and the great joy that comes from accepting and respecting Jewish pluralism
The four different kinds of tree products in the lulov and etrog are necessary for observing Sukkot, just as four different denominations (Orthodox, Conservative, Reform and Renewal) of Judaism are necessary for creating Jewish unity.
Joy results not from conformity to one path, or one interpretation of Torah. Joy results from the feeling of acceptance and caring for each other that comes from respecting religious differences within the Jewish People: a harmony in diversity.