Sukkah 43 - How many days?

Sometimes, the Talmud enumerates various possibilities of the Holidays falling on different days of the week and the resulting count of the mitzvot for the Holiday. For example, the mitzvah of the Sukkot bunch (lulav) could be done for either six or seven days. How so? Since the Holiday of Sukkot lasts for seven days, there invariably will be a Shabbat during Sukkot. However, when this Shabbat coincides with the first day of Sukkot, they would wave the lulav on that day, even on Shabbat. In other cases, the mitzvah of lulav would be done for only six days. And again, this was only when the Temple was standing. Today, people never wave the lulav on Shabbat.

In addition to the lulav, which is waved by every Israelite, there was a separate willow branch (aravah) that only the priests were required to take. With this aravah in their hands, they would circle the Altar. This aravah is special in that it is not mentioned explicitly in the Torah. There were always schools that taught that whatever is not mentioned explicitly in the Torah but is taught from teacher to student is not true. To emphasize that the aravah was true, it was allowed even on Shabbat, when this Shabbat coincided with the last day of Sukkot.

Art: Pollard Willows and Setting Sun by Vincent van Gogh