Mishnah 9 in chapter 4 of Maseches Sukkah deals with the mitzvah of the water libation - the pouring of water on the altar that took place on Sukkos, which was already mentioned in the first mishnah of the chapter. Our mishnah opens with a question: "Nisuch hamayim keitzad?" - how was this mitzvah actually carried out?
Filling the water and bringing it:
"Tzelochis shel zahav machzekes shloshah lugin" - a vessel made of gold, which was able to hold three lugin.
"Hayah memalei min haShiloach" - he would fill it from the waters of the Shiloach, the spring in Yerushalayim.
The bringing of the water concluded the Simchas Beis HaSho'evah - the celebration that continued all night long and ended with the acts described in our mishnah. The mishnah therefore describes the process of bringing the water.
"Higi'u l'sha'ar hamayim taku v'heri'u v'saku" - the Water Gate is the place through which the water was brought into the Azarah. Upon arriving there they sounded the trumpets: a tekiah, a teruah and a tekiah.
"Alah bakevesh u'fanah lismolo" - the kohen went up the ramp and immediately turned to the left. For most of the services performed on the altar they would circle the altar in order to reach the left side, that is, they would go to the right and circle around; here, however, so that the water would not be affected by the smoke, the ashes and the like, they turned directly to the left, to the place where the vessels into which the water was poured were set.
The two bowls:
"Shnei sefalim shel kesef hayu sham" - two bowls made of silver, with drainage channels running down into the altar. "Rabbi Yehudah omer: shel sid hayu, ela shehayu mush'charin peneihem bifnei hayayin" - according to Rabbi Yehudah the bowls were made of plaster, and originally they were white, and they appeared to be silver because they had been blackened by the wine that was poured into them. One bowl was used for wine and one for the water libation, and water does not blacken; rather, from time to time the wine was mistakenly poured into the water bowl and blackened it.
"U'nekuvim k'minei shnei chotamin hadakin, echad me'uveh v'echad dak" - they were perforated like two thin nostrils, one with a thick, wide hole and one with a finer hole. The reason for this: wine is thicker than water, and therefore it flows more slowly. For this reason the holes were made in different sizes - "kdei sheyihu kalim b'echad" - so that they would finish draining from the vessel through the channel at one and the same time.
The western bowl, the one closer to the Heichal, was designated for the water, while the eastern one was designated for the wine. And even if the water was mistakenly poured into the wine bowl or the reverse, the obligation was fulfilled. Although special, separate bowls were designated for each of them, the mitzvah is fulfilled in any case.
The dispute between Rabbi Yehudah and the first Tanna:
Rabbi Yehudah disagrees with the first Tanna on two points:
The measure of the water: according to the first Tanna three lugin are poured, and according to Rabbi Yehudah only one log.
The number of days: according to the first Tanna, as we learned in the first mishnah of the chapter, the libation is performed only on the seven days of Sukkos and not on Shemini Atzeres; and according to Rabbi Yehudah it is performed on all eight days, including Shemini Atzeres.
Raising the hand:
Let us return to the description of the process: they would tell the one performing the libation to raise his hand, so that it would be visible to all that he was indeed pouring the water into the bowl. The reason for this: the mitzvah of the water libation is a halachah transmitted to Moshe at Sinai, part of the Oral Torah, and it is not stated explicitly anywhere in the Written Torah. For this reason the Tzedukim, who believed in the Written Torah alone, opposed it and did not observe it.
And indeed, on one occasion one of those performing the libation poured the water on his feet instead of on the altar, acting in accordance with the practice of the Tzedukim. On the spot the entire people pelted him with their esrogim, throwing all their esrogim at him. From then on, in order to make certain that the one performing the libation was doing his work properly, they would ask him to raise his hand.
In summary: in this mishnah we learned the order of the water libation: filling a golden flask holding three lugin from the waters of the Shiloach, the arrival at the Water Gate with a tekiah, teruah and tekiah, going up the ramp and turning left to the two bowls - the western one for water and the eastern one for wine - whose holes differed in size so that they would finish draining together. We also examined the dispute between Rabbi Yehudah and the first Tanna regarding the measure of the water and the number of days of the libation, and the enactment to raise the hand following the incident of that man who poured the libation on his feet.