a. According to Lev. 23:40, a proper celebration of the festival requires the use of the arba minim, “four species.” The verse lists four species, which have been interpreted as follows:
“product of goodly trees ” = etrog (citron)
“branches of palm trees” = lulav (palm leaves bound together)
“boughs of leafy trees” = myrtle
“willows of the brook” = willow
b. In the synagogue on the first day of Sukkot, the four species are held in the hands and are shaken in all four directions, as well as up and down after the blessing is pronounced. This same ritual is done in the Sukkah as well and on all other days of Sukkot except on Shabbat.
The meaning of the shaking is that of harvest, since Sukkot symbolizes the final harvest of nations, when all nations will celebrate Sukkot (cf. Zechariah 14:16ff). The nations will be gathered to the worship of Israel’s God, and they will come from all directions of the compass. Thus, the four species (representing all kinds of peoples) will come from all over the earth to Israel to worship HaShem.
There are also Hashanot, circling (hakkafot) in parade fashion with the four species and reciting one of the Hashanot (“save us”) hymns (e.g., Psalm 106). Usually this is a circle around the synagogue, as a remembrance of the processions around the Temple during the 2nd Temple period. This is not done on Shabbat, but the Hashanot are recited without circling.
The meaning of this ritual is variously explained: a thankfulness for the harvest (much like the wave offering of the Temple period) is the most often cited meaning. From a Messianic perspective, the emphasis upon harvest, and the shaking of the four species in every direction, brings to mind both the promise of regathering Israel from the four corners of the world, and the promise to bless all the nations through Abraham, the harvest of the nations. It seems clearly for this reason that Sukkot is the festival chosen in the future reign of Yeshua as the celebration in which the nations participate (Zech. 14:16ff).
c. From a Rabbinic perspective, the first two days of Sukkot are considered full festival days (like all festivals outside of The Land), but days 3-6 are considered “intermediate days” (Chol haMoed). The Torah only specifies the first day and the eighth day (shemini atzeret, see below) to be sabbaths.
Traditionally, the first two days of Sukkot are marked by time in the Sukkah, etc., eating regular meals and reciting the festival blessings. There are some slight changes in the traditional synagogue liturgy. The seventh day is called Hoshana Rabbah, “the Great Hoshana.” (The word “Hoshanah” is actually two words combined, “save” and “please,” and is thus a shortened form of “help, I pray.” It was transliterated as “hossana” by English translators and has become a familiar word in Christian liturgy and music.) Normally, being the last day of the festival, it would be considered a full festival day. But the biblical text is a bit ambivalent, and it thus became tradition to add an eighth day, called Shemini Atzeret, and thus the festival of Sukkot is carried one day past its normal time. The text reads:
Again the LORD spoke to Moses, saying, “Speak to the sons of Israel, saying, ‘On the fifteenth of this seventh month is the Feast of Booths for seven days to the LORD. ‘On the first day is a holy convocation; you shall do no laborious work of any kind. ‘For seven days you shall present an offering by fire to the LORD. On the eighth day you shall have a holy convocation and present an offering by fire to the LORD; it is an assembly. You shall do no laborious work.
The question of interpretation is that the text first seems to indicate that the festival lasts seven days, yet it marks the eighth day as a sabbath. The sages intepreted this to mean that the seventh day marked the end of Sukkot, but the eighth day was a festival unto itself, while at the same time being an extension of Sukkot. The seventh day, then, is noted by a special ritual: the synagogue is circled seven times, rather than the single circling of the first six days. And, during the seven circlings, willows are beaten on the ground, and the Torah scrolls are carried in the parade. These “circlings” (called hakafot) are mentioned in the Talmud (b.Yoma 59a) and may have been traditional even earlier.
The eighth day, called Shemini Atzeret, “eighth day conclusion,” thus pictures the eternity, the eighth day of the cosmic week, and foretells the eternal dwelling of God with His people. In this way, the Festival of Sukkot, the last of the Torah cycle festivals, is a mini-picture of the whole history of the universe: seven days marking the scope of human history, and the eighth day (shemini atzeret) symbolic of eternity.