Sparks of Chassidus
A Mitzvah Of Unity:
The Mitzvah of Daled Minim represent unity in many factors:
Makes unity amongst the Sefiros of Atzilus: In general the mitzvah of the four species represents unity of the Jewish people, which is apparent in each of the four species as will be explained later on. This unity arouses the unity of the Divine Sefiros of G-D above in the world of Atzilus. Amongst the Sefirot there are opposing attributes, such as the attribute of kindness and of severity. In order to effect unity amongst these attributes there is required to bring down to their level a very high revelation of G-dliness which to that level both the attributes of severity and of kindness will be nullified to, and thus allow for their unification. It is this level of G-dliness which the four species arouse above to be drawn down to the world of Atzilus and thus cause the unity. Further on will be explained how physically each one of the four species contains aspects of unity in them.
Represents unity of the Jewish people: The aspect of unity is also apparent in the general unity of the four species being taken together. The Midrash explains how each one of the four species represents a different segment of Jewry, and how their being bound together represents their unity.
Each species itself contains unity: Thus there is a double aspect of unity in the four species. The unity found in each particular species, and the unity found by bringing the four species together.
The unity within the Lulav: Each of the four species including the Lulav contain a certain aspect of unity which differs from all other branches in the world. All trees have their branches grow in various directions from their stem and do not follow any pattern of growth, thus a regular tree whose leaves have fallen off appears like a stem with many different arms, each one going in its own direction, thus leaving areas on the stem’s branch empty being they have no branches growing. The palm tree however, from which the date derives, has its branches grow in a set pattern of growth, as each branch grows from directly on top of the branch below it, and thus all together forms a united pattern of branches which cover all of the palm’s area of branch growth. Thus we see that the palm tree differs in unity from all the other trees. It is a branch from this tree that G-D commanded us to take to use for the Mitzvah of the four species- the mitzvah of Unity.
The representation of the Lulav within Jewry: The Midrash explains that the Lulav represents the Torah scholars which spend the majority of their time learning Torah. The connection between the two is that Torah is referred to as something of good taste. This corresponds to the taste of the dates which derive from the palm tree of which the Lulav is taken from.
 Siddur Im Dach p. 524