Mishnah: The Mitzvos of Lulav and (circling the altar with the) Aravah are observed for six or seven days of Sukos.

Halel and rejoicing (eating the meat of a Shelamim sacrifice) are observed for eight days (which includes Shemini Atzeres).

Sukah and the water libations are observed for seven days (but not Shemini Atzeres).

The flute (one of the musical instruments played at the Simchas Beis Hasho'evah) is used for five or six days of Sukos. The Lulav is observed for seven days.

How is this? If the first day of Sukos occurred on Shabbos, the Mitzvah of Lulav is observed for seven days; if it occurred on a weekday, the Mitzvah is observed for six days.

When is Aravah observed for seven days? If the seventh day of Sukos occurred on Shabbos, Aravah is observed for seven days; if it occurred on a weekday, it is observed for six.

(Gemara - R. Zeira/ R. Ila/ R. Yasa quoting R. Yochanan): The Mitzvah of Aravah is a tradition from Har Sinai.

This is unlike Abba Shaul who says that its source is in the Torah -

"Arvei Nachal" - is plural (meaning two) - an Aravah for the Lulav and an Aravah for the Temple.

R. Ba/ R. Chiya quoting R. Yochanan: Aravah, water libations, and 'ten saplings' are a tradition from Har Sinai. (The Halachah is that a 'Beis Se'ah' sized field that contains ten saplings may be ploughed until immediately before the Shemita year, even though ploughing is usually forbidden from Shavuos of the 6th year).

This is unlike R. Akiva who said that the practice of water libations in the Temple (on Sukos) is written in the Torah (in Bamidbar Chap. 29) - On the second day (of Sukos) the Pasuk says "Venischayhem" (using an extra letter "Mem"); on the sixth day of Sukos, the Pasuk says "U'Nesacheha" (using an extra letter "Yud"); on the seventh day of Sukos, the Pasuk says "Kemishpatam" (using an extra letter "Mem") - these extra letters spell the word Mayim, meaning water, referring to the water libations.

Question (R. Chiya bar Ba to R. Yochanan): (You taught that the case of 'ten saplings' is a tradition from Har Sinai, but the implication was that the field of older trees may not be ploughed); if so, nowadays, why do we plough around older trees until Rosh Hashanah?

Answer (R. Yochanan): When the tradition was transmitted, it included the stipulation that if Beis Din perceive that there is a need to plough, it is permitted.

R. Ba bar Zavda quoting R. Chunya of Beras Chavran: Aravah, water libations and 'ten saplings' were decreed by the later prophets of the Men of the Great Assembly (Chagai, Zecharia and Malachi).

Question: Does R. Chunya disagree with R. Yochanan who said the they are a tradition from Har Sinai?

Answer (R. Yosi bei R. Bun quoting Levi): There was a tradition from Har Sinai, but it was forgotten and later re-established by the prophets. This teaches that whenever Beis Din make special efforts to understand and fulfill something thoroughly, it will ultimately be established by them as it was taught originally to Moshe at Har Sinai.

This follows the statement of R. Mana - the Pasuk states (Devarim 32,47), "it is not an empty matter [from you]". If it is empty, it is because of you, because you are not toiling in it. "As it is your life" - When is it "your life"? When you toil in it.

R. Yochanan to R. Chiya bar Ba of Bavel: Two things that you (Babylonians) said, are the Halachah - (a) One only prostrates with extended arms and legs on a public fast day; (b) taking the Aravah on the seventh day of Sukos is only a custom of the prophets.

Rabbanan of Kisarin: There is also the case of blood-letting. (They were accustomed to let blood only certain days - this custom later spread throughout the Jewish world). (Note: This entry follows the explanation of the Pnei Moshe.)

R. Simon ordered those that made the calculation of 'full' months to ensure that the 1st day of Rosh Hashanah does not occur on Shabbos and to also ensure that the 7th day of Sukos does not occur on Shabbos. If it is not possible to do both of these, they should preferably ensure that the 7th day of Sukos should not occur on Shabbos. (This is because even if the 1st day of Rosh Hashanah occurs on Shabbos, they can still sound the Shofar on the 2nd day. Alternatively, sounding the Shofar is from the Torah and does not require special strengthening; but Aravah is a tradition and must be strengthened.)