The Four Species
The Four Species are four types of plants that grow in Israel, for which a blessing must be said during the holiday of Sukkot while waving them in a special ceremony. The plants are Etrog, Lulav, Hadas and Aravah.
The Four Species are a symbol of the Israelites. The smell is a symbol for doing good deeds, and the flavor is a symbol for keeping the commandments of the Torah. There are many kinds of people, but just like the four species, all Israelites should stick together despite their differences.
The Origins of the Mitzvah
The mitzvah of waving the Four Species derives from the Torah. In Leviticus, it states: "And ye shall take you on the first day the fruit of goodly trees, branches of palm-trees, and boughs of thick trees, and willows of the brook, and ye shall rejoice before the LORD your God seven days."
Before the Temple in Jerusalem was destroyed, the waving ceremony was performed in it on all seven days of Sukkot, and in other places only on the first day of the holiday. When the Temple was destroyed, Rabbi Yohanan ben Zakkai ordered that the waving ceremony should be held on every day of Sukkot (besides Sabbath).
Preparation of the Four Species
To prepare The Four Species for the waving, the Lulav is first bound together with the Hadas and Aravah so that one Lulav is placed in the center, two Aravah branches are placed to the left, and three Hadas boughs are placed to the right. The bundle may be bound with strips from another palm frond, or be placed in a special holder which is also woven from palm fronds.
Sephardic Jews place one Aravah to the left of the Lulav and one to its right, and cover them with the three Hadas boughs: one on the right, one on the left, and one atop the Lulav's spine, leaning slightly to the right. The bundle is held together with rings made from strips of palm fronds. Many Hasidic Ashkenazi Jews follow this practice as well.
All of the species must be placed based on the direction in which they grew which means that the stem of the Etrog should point downwards.
Blessing over the Four Species
When blessing over the Lulav and Etrog one should hold the Etrog in the left hand, and the Lulav in the right (According to the Ashkenazi custom, left handed users should swap hands). The Sephardi custom is that the blessing is said only on the Lulav and the Etrog is picked up once the blessing is completed.
Before the blessing is said, it is the Ashkenazi custom to turn the Etrog upside-down, opposite the direction in which it grows.
The blessing over the Etrog and Lulav reads "Blessed are You, Lord our God, King of the universe, Who has sanctified us with His commandments, and commanded us to take the Lulav" (the "Shehecheyanu" blessing is also recited the first time each year that one waves the Lulav and Etrog), the Etrog is turned right side up (or picked up), and the user brings his or her two hands together so that the Etrog touches the Lulav bundle. The Four Species are then pointed and gently shaken three times toward each of the four directions, plus up and down, to attest to God's mastery over all of creation.
The waving ceremony can be performed in the synagogue, or in the privacy of one's home or Sukkah, as long as it is daytime. Women and girls may also choose to perform the mitzvah of waving the Lulav and Etrog, although they are not required by Halakha to do so.
The waving is performed again (though without the attendant blessings) during Morning Prayer services in the synagogue, at several points during the recital of Hallel.
Additionally, in the synagogue, Hallel is followed by a further ceremony, in which the worshippers join in a processional around the sanctuary with their Four Species, while reciting special supplications (called hoshaanot, from the refrain hosha na, "save us"). From the first through the sixth day of Sukkot, one complete circuit is made; on Hoshanah Rabbah, the seventh and last day of Sukkot, seven complete circuits are made. As the Four Species are not used on Shabbat, there are variant customs as to whether hoshaanot are said and a circuit made on that day.