In the Sukkah, we are all one because in essence we are a single being. But that which is outside our essence—that which makes us the individuals who we are—that is not yet one. In the unity of the Etrog, Lulav, Hadasim and Aravot, we are all one as distinct individuals, complementing one another to make a single, harmonious whole. But we remain apart at the core, united only superficially. When the two mitzvot come together, then we are one in all ways: The oneness of our essence...