סוכה ד׳:ב׳ - ד׳:ג׳

לולב שבעה – for the first day [of Sukkot] supersedes the Sabbath because it has the essential [principle] from the Torah outside of Jerusalem, as it is written (Leviticus 23:40): “ On the first day you shall take [the product of hadar trees, branches of palm trees, boughs of leafy trees, and willows of the brook, and you shall rejoice before the LORD your God seven days].”

ושאר כל הימים – if the First Day [of Sukkot] occurs on the other days of the week, and it is found that Shabbat occurs during the Intermediate Days of the Festival, it does not supersede [the Sabbath], and even though, from the Torah, all seven [are observed] in the Temple, the Sages preserved their decree on the other days of the Festival [of Sukkot] since they lack the principle from the Torah outside of Jerusalem. But by law, even in our times, the Lulav would supersede the Sabbath on the First Day of the Festival [of Sukkot], but because we are not expert in the establishment of the month, and lest that it is not the first day of the Festival, therefore, it does not supersede the Sabbath from doubt. But the reason that they (i.e., the Sages) decreed to not take up the Lulav on the Sabbath, for in taking it up, there is no [violation] of work other than merely carrying, and it was decreed lest he take it in his hand and would walk to someone expert to learn the blessing and the order of the Wavings [of the Lulav] and cause to pass four cubits in the public domain, and that is the reason for the Shofar [which is prohibited to carry on Shabbat] and that is the reason for the Megillah [which is prohibited to carry on Shabbat].

יום שביעי של ערבה כו' – for the sake of recognition to know that it is from the Torah, that is to say, a usage dating from Moses as delivered from Sinai (i.e., a traditional interpretation of a written law), and because of this recognition, it was established that its seventh [day] supersedes the Sabbath in the Temple, for with the willow, they would make a circuit around the altar. But today, it is not other than a custom of the Prophets that they directed the people to take the willow on the seventh day other than the willow in the Lulav, but we don’t make a blessing upon it.