Why did R. Avahu put his hands over his Ever?

Rashi: This was when bathing, for modesty.

How does holding the Ever while urinating cause a Mabul?

Rashi: It warms the Ever, which leads to emissions of semen. Dor ha'Mabul sinned with intentional Zera l'Vatalah - "Ki Hishchis Kol Basar."

Tosfos: Even though Rabanan permit holding the Ever while urinating (Nidah 13a), this is only lest drops of urine fall on his feet, and people will say that he is sterile, and his [alleged] children are Mamzerim.

Do soldiers enter a city in peacetime?

Rashi: This refers to soldiers of the local kingdom.

Open barrels should also be forbidden, due to Giluy (perhaps a snake drank from them)!

Rav Elyashiv: They are not totally open. They have a cover, but it is not sealed and plastered on.

Why was R. Avahu afraid of the river?

Rav Elyashiv: One who bathes there must be careful not to drown there. Until he totally leaves, there is fear, even when returning.

Why is putting one's hands over the Ever like denying Bris Milah?

Rashi: He shows that he is ashamed of it.

It should have said, it is like denying Bris Milah. Why does it say 'the Bris of Avraham'?

Maharsha: Noach and his sons had the filth of Orlah, which is despised. Therefore, it was forbidden for them to expose their Ervah in front of people. This is why Shem and Yafes turned away when covering Noach's Ervah. Avraham removed this filth via Hash-m's decree. Therefore, one who covers it, he does like Noach and his sons. The opposite shows the deed of Avraham.

Iyun Yakov: We find that Avraham circumcised himself in front of everyone - "b'Etzem ha'Yom ha'Zeh Nimol Avraham." One who covers it even when people are not around, it is as if he denies it.

What is the difference between descending to the river and returning from it?

Rashi: When descending, he does not face anyone. There is no concern for modesty, so he may not cover it. When he returns, he faces people on the bank; one may cover it for modesty.

Rav Elyashiv: When descending, he faces only individuals in the river, and they are bathing [naked], so it is like a bathhouse. There is no concern for modesty, so he may not cover his Milah, for it looks like he denies. When he returns, he faces people, so there is no Isur to cover. Just the contrary, it is modest to cover! Even though the Shulchan Aruch says that one must conduct modestly even when alone in a room, that refers to covering the entire body, and not just the Milah. Here he was naked, for he was bathing in the river!

Why did Rava bend over?

Rashash: The Gemara implies that he bent over even when descending. Covering it shows shame, but bending does not.

Rav Elyashiv: Bending is like covering. It is permitted only when ascending, but not when descending.

Why did R. Zeira walk upright?

Rashi: He was concerned for R. Aba's law.

Rav Elyashiv: Even though he saw R. Avahu put his hands over his Ever, he holds that modesty does not override R. Aba's law.

Why was R. Zeira avoiding Rav Yehudah?

Rashi: He feared lest Rav Yehudah decree that he not go.

Rav Elyashiv: The Halachah does not follow Rav Yehudah. However, if Rav Yehudah would explicitly command R. Zeira, it would be forbidden to defy his command. He went covertly [to hear another teaching], for presumably his intent to ascend was known. People would sell all their property before ascending (Kidushin 49a).

How did Rav Yehudah expound "Bavelah Yuva'u v'Shamah Yihyu Ad Yom Pakdi Osam", and why did R. Zeira disagree?

Rashi: (Rav Yehudah expounded that Yisrael must remain in Bavel until Hash-m redeems them.) R. Zeira held that the verse refers to Klei ha'Mikdash (Kesuvos 111a).

Iyun Yakov: Rif (on the Ein Yakov, Kesuvos 110b) asked, how could Hash-m command that they remain in Bavel? One who dwells in Chutz la'Aretz is like one who has no G-d! That is one who chooses to do so. Rav Yehudah expounds about those who were forcibly exiled to Bavel. Hash-m decreed that they stay there [until he will redeem them]. Tosfos says that even though the verse discusses Galus Rishon, the same applies to Galus Sheni. Granted, Galus Rishon needed to be in Bavel. Galus Sheni did not need to be in Bavel. They could go from Bavel to elsewhere. Why may they go from Bavel to other places in Chutz la'Aretz, but not to Eretz Yisrael? Also, we conclude that Rav Yehudah agrees that the verse refers to Klei ha'Mikdash; he expounds "Hishbati Eschem..." to forbid people to return. If so, why did he say that one who returns transgresses an Aseh? He transgresses a Shevu'ah! It seems that really, he learns from "Bavelah Yuva'u"; "Hishbati Eschem..." merely proves that "Bavelah..." is not limited to the Klei Shares (NOTE: surely, the text should say so - PF). Since we learn from "Hishbati Eschem...", it applies also to Galus Sheni, and from all lands to Eretz Yisrael, until Hash-m wants to redeem us.

Iyun Yakov: The Kedushah of Bavel is close to that of Eretz Yisrael. Their language is close to the Torah's language. We can say that one who dwells in other places in Chutz la'Aretz is like one who has no G-d, but not one who dwells in Bavel.

Rav Elyashiv: The Isur is only to go to Eretz Yisrael, for we must remain in Galus. Even though Hash-m returned us in the days of Ezra ("Pakadti"), since they were exiled afterwards, the Isur returned. Rav Yehudah agrees that the verse primarily discusses Klei Shares, just reasoning teaches that [Yisrael] must be in Galus, and not in Eretz Yisrael. Therefore, one may not ascend to Eretz Yisrael also from other lands. In Kesuvos (111a), Rashi explained that the Isur to go from Bavel to other lands is due to the Torah and Yeshivos in Bavel, just like the Isur to go from Eretz Yisrael to Bavel. The Ramban (Hasagos on Sefer ha'Mitzvos , Aseh 4) says that even nowadays, there is a Mitzvah to dwell in Eretz Yisrael. And so he wrote in Sefer ha'Zechus and his Perush on the Torah (Mas'ei). How can Rav Yehudah forbid to come to Eretz Yisrael? Megilas Esther disproved the Ramban from this. Some say that this depends on whether or not the Kedushah of Eretz Yisrael was permanent. We hold that it was permanent. If so, the Ramban properly said that even nowadays, there is a Mitzvah to dwell here. Rav Yehudah held that the Kedushah was not permanent.

Should he drink hot water of the bathhouse?

Rashi: He should drink hot water, even if it was heated for bathing [and not to drink it].

Ya'avetz: i.e. he does not drink water in which he bathed, rather, Stam hot water. How can he bless in the inner room, where people are naked? Perhaps he need not bless, like one who drinks because he is choking.

Rav Elyashiv: He does not benefit from the drinking, for the water was intended for bathing. Nowadays this is dangerous, but in their days there was benefit. (NOTE: Water for bathing is slightly more than body temperature. This causes bacteria to multiply greatly. Water for drinking is boiled; this kills the bacteria. - PF) Presumably, he did not bless on the water, for it was not pleasurable; it was only for health. Tana'im and Amora'im did not go to the bathhouse for pleasure, rather, for health, and to broaden the mind to enable Avodas Hash-m.

What heat comes out?

Rashi: It is heat of sweat.

What is the problem with eating and not walking four Amos?

Rashi: He ate and did not walk four Amos before going to sleep. The food will rot inside him - this leads to bad breath.

What is an odor of filth?

Rashi: His entire body is constantly filthy with sweat.

What is the comparison to an oven ignited externally but not internally?

Rashi: This does not help at all.

What is the comparison to iron heated in the fire that was not put in cold water?

Rashi: When it is put in cold water, this strengthens (solidifies) it].

What is the comparison to water on top of a barrel?

Rashi: It does not enter.