LEV932 The mitzvah of taking a lulav on Sukkos. A person is most strongly influenced by the actions that he does on a regular basis. If his actions are virtuous, his thoughts will be the same. Since Hashem wants to bestow merit on His nation, He gives us many mitzvos, so that we are fulfilling His Will at all times and our thoughts and souls are constantly turned to good and virtue. Included in the mitzvos that Hashem commands us to help us to focus our thoughts on serving Him in purity, is the mitzvah of tefillin. They are worn next to the heart and brain, and when putting them on every day we dedicate our hearts and minds to His service. Thus, we are helped to remember and be sure that all day long we weigh our every deed according to the scales of justice and truth. This is the key concept of the Four Species. Sukkos is a time of great joy for the Jewish nation, for it is the time for bringing in our harvest of grain and fruits. Therefore, Hashem commands us to celebrate a festival at this time so that the primary joy in our hearts is in His Blessed Honor. Reaping one’s harvest tends to lead a person towards materialism and the joy at harvest time therefore can lead us to forget fear of God. Therefore, He commands us that on Sukkos we take in hand visible reminders that all of our joy is in His Blessed Honor. He commands us to take these four species because there these are species that give joy to all who see them. Another concept of the mitzvah is that the four species allude to four primary components of the human body. The esrog alludes to the heart--where human intelligence resides. By taking an esrog in hand on Sukkos, we are taught that in order to serve our Maker properly, we must use our intelligence. The lulav alludes to the spinal cord, which has central importance for all that we do, and taking it in hand teaches us to bring all of limbs in line with Hashem's Will. The hadas is shaped like the human eye, and we take it in hand on Sukkos in order to impress upon ourselves that during joyful days we must be particularly careful to not stray after our eyes. The willow leaf is shaped like our lips, which we use for speech, and taking it in hand teaches us to consider our words carefully so that we say nothing improper, for even during times of joy we must retain our fear of God. As to waiving the four species in all six directions, this serves to remind us that everything is from Hashem--what is above, what is below, and whatever is found in the north, south, east or west. This is how these matters appear according to the simple understanding. The cap Kabbalists expound many wondrous and more profound explanations for the mitzvah of the Four Species.