People who pay attention to what they read realize that none of the Jewish holidays are practiced today as the Torah mandates. Judaism today is not Torah Judaism but Rabbinic Judaism. The rabbis made extensive changes in Torah laws because of changes in human circumstances. Scholars think that the holidays were originally folk harvest festivals that were later given religious significance. I say all this even though I am an Orthodox Jew and obey all the rules the rabbis set for us.
What do we know about Sukkot?
The fall holiday of Sukkot begins on the fifteenth day of the seventh Jewish month and lasts for seven days. It generally occurs in September or October. The biblical rules of Sukkot are mentioned in five places: Exodus 23:16, 34:22; Leviticus 23:23-43; Numbers 29:12-39; Deuteronomy 16:13-15. Leviticus 23:40 states that the Israelites should take four species on the first day and “rejoice before the Lord your God seven days.” While the Hebrew words used for the four species are obscure, the JPS 1960 translation defines them as “the fruit of goodly trees, branches of palm trees, and boughs of thick trees, and willows of the brook.” An apparently separate command in verse 42 states “Ye shall dwell in booths seven days.” But is it separate?
The first biblical description of the implementation of this or these biblical command(s) is in Nehemiah. It is entirely different than the way the holiday is celebrated today. It is as if the author of Nehemiah who states he read the law in the Torah, had a different text. The holiday is not called Sukkot but Hag, the holiday. Not four but five items are taken and at least three of the five, and perhaps four, seem unlike the four mentioned in Leviticus. And most startlingly, the people were told to use the five items as the materials to build sukkot.
Scholars differ when Nehemiah lived and when the book carrying his name was edited. Many agree that these events occurred about a century after some Judeans returned to Judea after the Babylonian exile. He may have lived around 440 BCE, but perhaps later. The book states in 8:17, that the holiday had not been observed since the days of Joshua. In 8:14, the book records that the Judeans “found written in the Torah how the Lord had commanded Moses that the Israelites should dwell in booths (sukkot) in the holiday (chag) of the seventh month [and should proclaim] ‘Go to the mountain and fetch olive branches (zayit), and branches of wild olive (eitz shemen), and myrtle (hadas) branches, and palm (temarim) branches, and branches of thick trees (eitz abot) to make booths (sukkot).’”
The fact that the holiday is not called Sukkot in Nehemiah, but Hag, the practice of taking four species is not mentioned, and the key practice was to build a sukkah made of five species, seems to support the view that the holiday was named Sukkot after 440 BCE when its practices and significance were changed and that the biblical mandates were placed in the Torah during this later period.
This is the view of Arnold Ehrlich in his Mikra Ki-Pheshuto (The Bible According to its Literal Meaning). He writes that originally the ancient Israelites celebrated only one harvest festival. It was the fall festival which concluded all the harvests and was simply called Hag, “the festival.” Passover and Shavuot did not exist at this time. His view is supported by I Kings 8:2, 65; Nehemiah 8:14; II Chronicles 5:3 and 7:8 where the holiday is called Hag and there is no mention of Passover and Shavuot. Also, when the Jeroboam led the ten tribes, succeeded from Judea, created a new country Israel, and changed the holiday Hag from the seventh to the eighth month to differentiate Israel’s worship from the traditional worship in Judea, the holiday is called Hag in I Kings 12:32. Jeroboam did not change Passover and Shavuot because they did not exist. Additionally, Ehrlich argues, Leviticus 23:43 states that the reason for dwelling in sukkot is because the Israelites dwelt in sukkot when they left Egypt. This seems to be a late forced interpretation. There is no mention in the biblical texts that the Israelites dwelt in sukkot except for this verse. Secondly, if the holiday is celebrated as a recollection of how the Israelites lived when they left Egypt, the holiday should have been celebrated in the spring, during the season when the Israelites left Egypt. The rabbis were bothered by these questions and one rabbi responded that the sukkot that the Bible is referring to is the cloud that are mentioned in the Torah (Exodus 13:21) that covered the Israelites during the forty years in the desert and protected them, and the holiday is celebrated in the fall because of its second significance of being a harvest festival.
When did the holiday called Sukkot, in contrast the harvest holiday Hag, begin? Ehrlich imagines that in ancient times the Israelite pilgrims coming to the then small Jerusalem to celebrate Hag were unable to find lodging and had to make do with hastily constructed booths (Hebrew, sukkot). This was so onerous that many pilgrims stayed home. To counteract this “strike,” Israelite leadership, most likely the priests of the second temple period, mandated that all Israelites dwell in sukkot during Hag as a way of joining the pilgrims who had traveled to Jerusalem. The priestly plan worked. Since the Israelites had to dwell in sukkot wherever they were located, they resumed coming to the temple during Hag and the holiday assumed the name of its main practice. The prophet Zechariah, who lived at this time, called the holiday Sukkot, and seems to have addressed this problem of non-attendance in Jerusalem. He warned the people that if they do not travel to Jerusalem for this holiday “there shall be no rain” (14:17). He does not mention Passover or Shavuot.
 This essay is from my book “Mysteries of Judaism.”
The Sadducees, Samaritans, and Karaites also understood the Leviticus command to construct the sukkah of these items. Each is arguably reflecting the ancient practice. Even in the Babylonian Talmud, Rabbi Yehudah in the Sukkah 36b, said “The sukkah must be constructed of the same four species as the lulov,” although Rabbi Meir ruled that the sukkah can be made of any material. Rabbi Yehudah’s view may reflect some recollection of the ancient practice.
 This may mean that the holiday was not observed in this manner in the past, but was observed as a harvest festival.
 This is the view of one rabbi in the Babylonian Talmud Sukkah 11b. Another rabbi stated that the booth mentioned in Leviticus 23:43 was actual booths. The biblical commentators also disagreed. Rashi wrote they were clouds of glory and Nachmanides, who stressed that miracles occur daily, agreed. Rashi’s grandson Rashbam, who felt that we need to read the Torah to find its simple meaning, its pshat, sided with the talmudic rabbi who stated they were actual booths. Ehrlich also took the latter view. He argued that clouds are not huts; at most they are ceilings without walls.
 Ehrlich states that some Israelites objected to the new requirement to dwell in huts for seven days. He feels that these resisters inserted into Genesis 33:17 that when the patriarch Jacob returned to Canaan he built a house for himself and sukkot for his cattle, for sukkot are only fit for animals.