QUESTION: Rav and Shmuel disagree (end of 54b) about the minimum number of sheep that the middle flock needs in order to join the two outer flocks (which are a distance of more than 32 Mil from each other) to be counted together for Ma'aser Behemah. Rav maintains that the middle flock connects the outer ones only when there are enough sheep in the middle flock such that when it combines with either one of the outer flocks, there are more than ten sheep (and the obligation of Ma'aser applies). Shmuel rules that a flock of any size joins the outer flocks.
Whom does the Halachah follow?
ANSWER: The RAMBAM (Hilchos Bechoros 7:3) rules like Rav, presumably because the Halachah follows the ruling of Rav whenever he and Shmuel disagree in matters of Isur and Heter.
However, in this case, the general rule that the Halachah follows Rav in matters of Isur and Heter does not seem to apply. After the Gemara records the argument between Rav and Shmuel, the Gemara quotes Rav Papa who gives additional rulings "according to Shmuel," and Rav Ashi who asks about certain cases according to Shmuel. All of their statements are made only according to Shmuel's opinion. In general, when the Amora'im in the Gemara discuss the Halachic ramifications of one of two opinions, that shows that the Halachah follows that opinion. Accordingly, it is not clear why the Rambam rules in accordance with Rav in this case, and not like Shmuel. (M. KORNFELD)
OPINIONS: Rabah bar bar Chanah in the name of Rebbi Yochanan says that only the part of the Yarden (Jordan River) from Beis Yericho and below is considered the Yarden with regard to Ma'aser Behemah. (The simple meaning of "below" Beis Yericho seems to mean south, or downstream of Yericho, towards the Dead Sea. However, TOSFOS (DH Ein) apparently understands that the word "below" refers to the part of the Yarden that is north of Yericho.)
What is the difference between the part of the Yarden that flows below Beis Yericho, and the part of the Yarden that flows above Beis Yericho?
(a) RASHI (DH mi'Beis) explains that the part of the Yarden above Yericho is not called "Yarden" because from that point onward the river is secondary to the other bodies of water through which it flows.
(b) TOSFOS (DH Ein) disagrees with Rashi. If the Yarden is not called "Yarden" past Yericho because it mixes with other bodies of water, then why should Yericho be the cut-off point? The Yarden meets no other bodies of water until the Dead Sea in the south and the Kineret in the north, both of which are far from Yericho. Tosfos asserts that it must be that the cut-off point is defined by the verse in Yehoshua that the Gemara quotes earlier ("veha'Yarden Yigbol Oso") and is not related to its mixing with other bodies of water.
In defense of Rashi's explanation, perhaps one may suggest that Rashi understands the word "Beis Yericho" not to refer to the city of Yericho itself, but to the entire valley of Yericho (the Jericho Valley). From the Kineret until the Dead Sea is Beis Yericho. Accordingly, from the beginning of the Jericho Valley, south of the Kineret, the Yarden is considered significant, while north of the Kineret it is secondary to the other bodies of water. (M. KORNFELD)


QUESTION: The Gemara relates that the father of Shmuel instructed his daughters to immerse only in a Mikvah during Nisan, but during Tishrei he permitted them to immerse in a river. Why did he prohibit them from immersing in a river during Nisan?
(a) RASHI (DH Mikvah) explains that Shmuel was concerned that his daughters might be Zavos (women who experienced three consecutive flows of blood beyond their normal cycle) who must immerse only in Mayim Chayim (spring water, as opposed to rain water). He was afraid that in Nisan, immediately following the rainy season, the waters of the rivers might be mostly rain water, and their immersion would be invalid.
Rashi in Shabbos (65b, DH v'Savar), however, questions this explanation. The Tosefta clearly states that only a Zav (a male who experienced three consecutive discharges) must immerse in Mayim Chayim, and not a Zavah. Even if Shmuel's daughters were Zavos, immersion in water that was not Mayim Chayim would have been a valid immersion.
(b) RASHI here and in Shabbos suggests another explanation. Rain water is like Mayim She'uvim, water that has been drawn in a vessel, and is valid only for Tevilah b'Hamshachah (when the Mayim She'uvim is collected near the Mikvah, and it flows to and connects with the Mikvah). Shmuel was concerned that most of the rain water had fallen directly into the river, making it invalid for Tevilah.
Rashi in Shabbos, however, disproves this explanation as well based on a Mishnah in Mikva'os that states that rain water is valid for a Mikvah.
(c) RASHI in Shabbos (65b, DH v'Savar) and TOSFOS here (DH Shema) explain that in contrast to fresh water (from a river or spring), which makes a person Tahor even if he immerses in it while it is in motion, rain water makes a person Tahor only when it is stationary. Shmuel was concerned that most of the water in the river was rain water, which is not valid for Tevilah when it is flowing. (See following Insight.)
OPINIONS: Rav and Shmuel disagree about the source for the swelling of the waters of a river. Rav says that the increased size of a river is due to rainwater. Shmuel says that a river swells from its source, and thus its water is still considered natural river water. According to Rav, one may not use such a river as a Mikvah, since the water in the river has the status of rainwater, and rainwater may not be used for a Mikvah unless it is gathered in one place and is not flowing. According to Shmuel, the river may be used for Tevilah because it is treated like a natural stream, and a natural stream is valid for Tevilah when it is flowing.
The Gemara says that Shmuel himself did not rely on his own opinion in practice, and he said that one should not immerse in the Euphrates River except during the season of Tishrei, since there is no concern for rainwater at that time of year. The Gemara also relates that Shmuel's father also made special Mikva'os for his daughters in the month of Nisan (when the rivers expanded from the rainwater) in order for them to have a place to immerse (see previous Insight).
In practice, may one use a river as a Mikvah for Tevilah?
(a) RABEINU TAM rules in accordance with the statement of Shmuel that a river's waters increase from the river's own subterranean sources, and therefore one may immerse in a river throughout the year. Rabeinu Tam writes that Shmuel's opinion is supported by the Gemara earlier (55a) that says that the Euphrates River is called "Pras" because its waters are fruitful (Parin) and multiply.
Rabeinu Tam adds that even those who prohibit Tevilah in rivers during certain seasons (based on the rulings of Shmuel's father and the other Amora'im) would agree that all rivers in Eretz Yisrael are fit for Tevilah. Since Eretz Yisrael is higher than all other lands (Zevachim 54b), its rainwater drains away and its rivers flow solely from subterranean sources. (See Mikva'os 8:1, "Eretz Yisrael is Tahor and its Mikva'os are Tahor.") In addition, they would agree that the same reasoning might apply to all other rivers in mountains.
Rabeinu Tam points out that all of the Amora'im agree that according to Torah law one may immerse in a river even during the rainy season. The Rabanan prohibited Tevilah in a river due to Mar'is ha'Ayin (it looks as though the person is immersing in rainwater). He offers two logical explanations for this assertion. First, rain water trickles into the river drop by drop and is therefore annulled by the river water. Second, all rivers join with the sea at some point (Koheles 1:4), and since the sea is valid for Tevilah, the rivers are as well.
(b) RABEINU CHANANEL and the RIF disagree with Rabeinu Tam. As the RAMBAN points out, one may not rely on the Gemara here that explains the meaning of the name of the Euphrates to resolve the Halachic dispute between Rav and Shmuel, because a Gemara of Agadah cannot override a Sugya that discusses the practical Halachah (see Insights to Nedarim 40:6).
HALACHAH: The REMA (YD 201:2) writes that where there is no Mikvah nearby, the custom is to rely on Rabeinu Tam's ruling that one may immerse in a river throughout the year, provided that it is known that the river flows even during the summer months when there is no rain.
In practice, however, since the situation varies in different places and at different times, each question must be brought to a competent rabbinical authority. There are other difficulties involved with using the water at a beach as a Mikvah. (See the RAN who writes that Shmuel's father made mats for his daughters in order to prevent problems of Chatzitzah, and who cites those who rule that there is a need for a partition for purposes of modesty. See also Nidah 66b.)
(See also Insights to Shabbos 65:2 and Nedarim 40:5.)