Gemara: Ba'ish (ill).

Translation: 'Ba'ish' means ill.

Explanation: It seems to me that it means that as follows. Sometimes one must request mercy for a Choleh that he die, e.g. he is greatly pained in his illness and it is impossible for him to live.

Source: We say in Kesuvos (104a) that when Rebbi's Shifchah saw how many times he went to the privy and [afterwards] put on Tefilin, and he was pained, she said "may it be Your will that the higher beings overcome the lower beings (people praying that Rebbi live)", i.e. Rebbi should die.

This is why it says that one who visits a Choleh, his Tefilah helps even that he should live, for it is a Tefilah that helps more;

One who does not visit a Choleh, it goes without saying that he does not help him to live. Rather, even when there is benefit in death, even that small amount he does not benefit him. (Perhaps the Ran discusses one who does not visit, and does not pray for him. Alternatively, he prays that he live, but it is as if it does not help, for had he seen his illness, he would have prayed far better. - PF)

Gemara: One should not visit.

Explanation: The Targum of "u'Fkudas Kol ha'Adam" is v'Si'ada. (Note: Also Toras ha'Adam (Sha'ar ha'Michush DH b'Maseches Nedarim) says so. Our text of Onkelos is 'u'Se'ura'. - PF)

Gemara: A Choleh, in the first three hours, he feels well.

Explanation: The visitor thinks that he was healed, and he need not request mercy for him.

Gemara: In the last three hours, he is very weak.

Explanation: [The visitor] thinks that there is no hope, and he despairs from requesting mercy for him.

Gemara: He may not sit on a bed or bench.

Limitation: There is an opinion that this is only when the Choleh lies on the ground, so [if the visitor sit on a bed or bench] he is higher than the place of the Shechinah.

Explanation: When there is rain in Eretz Yisrael, the Pras (Euphrates river) in Bavel testifies to this. Whenever it (the water level) is high, it is known that even if rain did not fall here [in Bavel], rain fell in Eretz Yisrael.

Consequence: One may not immerse in it [then], because rainwater that is Notef (drips into a river) is not Metaher [like a Mikveh] when it is flowing, rather, only if it is Ashboren, i.e. contained and still.

Source (Sifri - Beraisa) Suggestion: Perhaps just like a spring is Metaher when it is flowing, also a Mikveh is Metaher when it is flowing!

Citation (cont.) Rejection: "Ach Mayan u'Vor [Mikve Mayim Yihyeh Tahor]" - a spring is Metaher when it is flowing, and a Mikveh is Metaher [only] if it is Ashboren.

Ruling: Therefore, whenever there is concern lest Notefin became the majority over flowing water [from underground sources], it is forbidden [to rely on Tevilah in it], i.e. when the river is very high;

However, if it was flowing slowly, or it increased only a little, so there is no concern for a majority of Notefin, it is permitted.

Support (Tosefta): R. Eliezer bar Tzadok testified about flowing water that became the majority over Notefin, that it is Kosher [for Tevilah].

Explanation: "Mi'Kipei" means from its rock, i.e. it increases from its source. Even though we see that when rain falls, rivers increase, the primary increase is from the source.

Source: We say in Ta'anis (25b) that for every Tefach [of rain] that descends from above, [the water in] the depths below rise two Tefachim to meet it;

It turns out that flowing water is always the majority over Notefin, since for every Tefach of rain, there are two Tefachim of spring water.

Consequence: Therefore, according to Shmuel, one may always immerse in rivers, even when it is evident that they increased greatly due to rain.

Gemara: He contradicts himself, for Shmuel said that [Tevilah in] flowing water is not Metaher.

Explanation: There is concern lest Notefin (rainwater, which drips) became the majority.

Explanation: This is because [Tishrei] is not a time of rain, and not a time of melting snow.

Assertion: [Shmuel] does not come to forbid [relying on Tevilah in] all rivers other than the Pras, and also he does not forbid the Pras the entire year except for Tishrei;

Since the whole concern is lest Notefin become the majority over flowing water, as long as we are proficient about the Pras in Tishrei, [and know] how high it (the water level) is, and similarly for other rivers...

If we know that it never goes below this level, even at a time of great drought, whenever we see only that amount [of water], why should we be concerned for it? There is no concern lest Notefin become the majority over flowing water!

Explanation: Rather, Shmuel teaches two matters. Firstly, rivers that sometimes dry up, one may never immerse in them. Since sometimes they dry up, we are always concerned for rainwater or melting snow;

Source (Parah 8:9 - Mishnah): Water (rivers) that [sometimes] dry up are Pasul [to put ashes of Parah Adumah on water taken from them]. These are called waters that dry up - those that dry up once in seven years. Those that dry up amidst great armies [who supply themselves from it] or in drought years are Kosher.

Explanation: All waters that dry up without an excuse, even if they dry up only very sporadically, i.e. once in seven years, are Pasul. We are concerned lest they are [mostly] rainwater, and they are not Metaher when they are flowing, rather, only Ashboren;

However, those that dry up due to an excuse, i.e. great armies or in drought years, are Kosher.

Support: This is why Shmuel said that the only flowing water that is Metaher is the Pras and similar [rivers] that never dry up. He said Pras to exclude rivers that dry up. He refers to Pras and similar [rivers];

Explanation (cont.): Shmuel teaches also that the Pras, and similar rivers that do not dry up, one may not immerse in it Stam the entire year if one is not proficient about it, only in the days of Tishrei, for it is not a time of rain or melting snow;

Therefore, even one who is not proficient about it, need not be concerned lest Notefin became the majority;

However, one who is proficient about Pras, and similar rivers, as long as he sees that it did not increase above its flow in Tishrei, that it would be proper to be concerned lest Notefin became the majority, he may immerse in it the entire year.

Similarly, if one sees in Tishrei that the water increased so much that it is possible to be concerned lest Notefin became the majority, even in Tishrei he may not immerse in it.

Rather, Shmuel said Stam that one who does not know, even for rivers that do not cease, he must be concerned the entire year for their increase, and in Tishrei he need not be concerned. So it seems to me.

I saw someone who wrote oppositely. I disagree.

Gemara: Shmuel's father made Mikva'os for his daughters in the days of Nisan.

Explanation: Because he was concerned for melting snow, he did not let them immerse in flowing water.

Explanation #1: [He put mats] in the river, under their feet, due to the mud, lest it be a Chatzitzah.

Explanation #2: [He put mats] merely for privacy [lest others see them immerse].

He let them immerse in the river, for in Tishrei, there is no concern for Notefin.

Opinion #1: "In the days of Nisan" means from Nisan until Tishrei, and all the more so during the winter. So [Meforshim] explained.

Rebuttal: The words connote unlike this. [If so] it should have said that he made Mikva'os for his daughters the entire year, and put mats in the days of Tishrei!

Opinion #2: Therefore, it seems to me that the daughters of Shmuel's father did not immerse in the river in winter, due to the cold, rather, in Mikva'os in their house;

In the days of Nisan, when the world is more comfortable (warmer), they began to immerse in the river, and at the beginning of Nisan he made for them Mikva'os there (in the river), in which they immersed until Tishrei;

In the days of Tishrei he did not obligate them to immerse in Mikva'os, for there is no concern for Notefin. Therefore he fixed for them mats;

When the days of Tishrei passed, they already returned [to immerse in Mikva'os] in their houses, due to the cold.

Opinion #1: R. Tam ruled like Shmuel, that a river increases [primarily] from its source.

Implied question #1: Rav argues with him, and when Rav and Shmuel argue, the Halachah follows Rav in Isurim (Bechoros 49b)!

Implied question #2: Also Shmuel's father holds like Rav, and Shmuel's other teaching also argues with this teaching of Shmuel!

Answer: Even so, we hold like Shmuel, for a Beraisa in Bechoros (55b) says "its name is Yoval. It is called Pras, because its waters increase. This is R. Meir's opinion";

Citation (55b): Chachamim say, "its name is Pras, because its waters increase." This supports Shmuel, who says that a river increases from its source.

Implied question: Shmuel said so about all rivers, that they increase from their sources. Chachamim say so only about the Pras!

Answer: Even so, this supports him. Since Pras increases from its source, also all rivers increase from the source of the Pras, for all rivers draw from the Pras, like we say there in Bechoros (55a);

Citation (55a): One who vows [not to benefit from] the Pras is forbidden all waters. Even elevated springs [on mountains higher than the Pras, draw from] 'ladders' [in the ground] from the Pras.

Conclusion: The Beraisa supports Shmuel, both from R. Meir and from Rabanan. Also Rabanan say that its name is Pras, because its waters increase.

Since R. Meir and Rabanan support Shmuel, we follow his opinion.

Summation: According to this opinion, one may always immerse in rivers, even when they increase greatly due to rainwater, since for every Tefach [of rain] that descends from above, the depths rise two Tefachim to meet it. This is R. Tam's opinion.

Limitation: It seems that even he said so only regarding rivers that do not cease. For rivers that cease, we cannot say that they increase from their sources!

Opinion #2: However, R. Chananel and the Rif ruled like Rav and Shmuel's father, that the only flowing water that is Metaher is the Pras in Tishrei.

Explanation (Ramban): Even though Shmuel taught that a river increases from its source, we do not reject a teaching about an Isur that was followed in practice, like Shmuel's father, who made Mikva'os for his daughters, due to an Agadic (non-Halachic) teaching;

Also Shmuel did not say (that for every Tefach that descends, the depths rise two Tefachim) in practice, for he taught also that flowing water is not Metaher [except for...]

This implies that granted, letter of the law it is permitted, but in practice we should be concerned.

Support: This is like it says elsewhere "now that Shmuel said 'it is forbidden', and Tana d'Vei Shmuel permits, Shmuel comes to teach Halachah in practice."

Implied question: The Gemara said that Shmuel contradicts himself! (According to the Ramban, there is no contradiction.)

Answer: It means that it is not the case that both his teachings are true. Only one of them is. If one is true, the other is not;

However, he does not contradict himself. He is merely concerned in practice.

Support: The Gemara in Nidah (67a) connotes like this. We bring what Shmuel's father did, and we do not conclude that it is unlike his son;

Inference: Also Shmuel is concerned in practice.

Question: Why is he concerned? R. Meir and Rabanan say in a Beraisa in Bechoros (55b) that the Pras' waters increase!

Also, why do Shmuel's father and Rav hold that it does not increase from its source?

Answer #1: They knew that there are Tana'im elsewhere who disagree [with R. Meir and Rabanan].

Answer #2: There are texts that do not say in Rabanan's words "its waters increase", rather, only "Chachamim say, its name is Pras."

Consequence: According to this, the support there for Shmuel is from R. Meir, but not from Rabanan;

Even so, we properly infer from R. Meir, for Rabanan do not explicitly argue to say that it does not increase;

Rav, and Shmuel's father, hold that Rabanan argue with him, and also Shmuel is concerned [in practice].

Conclusion: According to this (the Ramban's explanation of R. Chananel and the Rif), we do not immerse at all in rivers that cease. We are always concerned about them for rainwater and melting snow;

Big rivers that do not cease, anyone who is proficient about them and knows their primary flow in Tishrei, he may immerse in them the entire year, as long as he sees that there is no concern lest Notefin became the majority over its primary flow;

However, whenever he sees from their increase that there is concern for this (a majority of Notefin), even in Tishrei he may not immerse in them.

One who is not proficient about them, the entire year he must be concerned for them, except for in the days of Tishrei. In Tishrei, Stam Notefin are not the majority.

Opinion #3: There is an opinion that when we are concerned lest Notefin became the majority over flowing water, this is only to immerse in them in a place where the river did not flow beforehand;

However, in a place where it flowed initially, even though now Notefin became the majority over flowing water, one may immerse there.

Proof - Citation (Mikva'os 1:7 - Mishnah): If a spring had little water, and Mayim She'uvim (water that was in a Kli) became the majority, it is like a Mikveh to be Metaher b'Ashboren (contained, still water), and it is like a spring to immerse [Kelim] in any amount [of water];

Note: R. Shimshon and R. Tam explain that it is Metaher only Kelim in any amount, but 40 Sa'im are needed for Tevilah of people. The Ran holds like the Rambam and Ra'avad, that also for people, there is no Shi'ur (Tosfos Yom Tov). Perhaps the Mishnah says Lehabtil (Kelim) to teach that any amount suffices, e.g. for pins. Much water is required to totally surround a person's body. Some have the text "Letaher", which applies equally to people.

Inference: Since it says "it is like a Mikveh to be Metaher b'Ashboren", this shows that it has the law of a Mikveh, which is not Metaher through flowing water, for it does not have the law of a spring. Rather, it is like a Mikveh, which requires Ashboren.

Contradiction: Later, it teaches "and it is like a spring to immerse [Kelim] in any amount." Surely, since it taught "it is like a spring to immerse [Kelim] in any amount", likewise it is Metaher through flowing water, since it has the law of a Mayan (spring). The Reisha contradicts the Seifa!

Resolution: Rather, surely it means that this spring in which Mayim She'uvim became the majority, in some places it has the law of a Mikveh, and it requires Ashboren. These are the places where it flows now, due to the added Notefin, and it did not flow there initially;

And it has places in which its law did not change from like it was. Rather, it is [still] like a spring to immerse [Kelim] in any amount. This is where even initially, it flowed there.

Implied question: Why didn't it teach 'it is like a spring to immerse in flowing water', or teach in the Reisha 'it is like a Mikveh, and it requires a Shi'ur (40 Sa'im)'?

Answer: It seems to me that that it taught so in order to teach two laws in a Mikveh and spring, and each one is inferred from the other;

Since the Reisha taught "it is like a Mikveh to be Metaher b'Ashboren", this implies that the place that is like a spring, which the Seifa teaches, does not need Ashboren;

Since the Seifa taught "it is like a spring to immerse [Kelim] in any amount", [this implies that] the place that is like a Mikveh, which the Reisha taught, requires a Shi'ur.

Inference: We learn from this [Mishnah in Mikva'os] that there a place in a spring, that even though it increased due to Notefin, it has the law of a spring, i.e. where it flowed initially.

Support (Tosefta Mikva'os 1:15): If a spring had little water, and it increased and widened due to Notefin, it is Metaher b'Ashboren.