1) LEAVING AN ANIMAL AT AN INN
QUESTION: The Mishnah states that we may not "stand" animals ("Ein Ma'amidin") in inns of Ovdei Kochachim, because the Nochri innkeeper might be attracted to the animal, and the Jew will have caused him to sin, thereby transgressing the Isur of "Lifnei Iver."
Earlier (14b), when Rav refers to this Mishnah, he says that the Mishnah prohibits "Yichud," isolating an animal with a Nochri. Why does the Mishnah use the phrase "Ein Ma'amidin" rather than "Ein Meyachadim," as the Mishnah itself says with regard to a Jewish man or woman being alone with a Nochri? (NETZIV in MEROMEI SADEH)
Also, RASHI explains that "Pundaka'os" are places that provide board for travelers. He adds that the guests at the inn pay the owners for their services. Why does Rashi add that the travelers pay for the services of the innkeeper? If one is prohibited from leaving an animal alone with a Nochri, then what difference does it make whether or not the owner of the animal pays the Nochri innkeeper? (HAGAHOS HA'BACH on the RIF)
ANSWER: TOSFOS (23a, DH v'Su) points out that a Nochri is suspected of Revi'a only when the animal is placed in the care of the Nochri. Accordingly, perhaps the Mishnah's intention is to teach that there is no prohibition to leave one's animal isolated with a Nochri; it is only when one places his animal under the Nochri's care that the Nochri might take advantage of having the animal, since he was given the right to approach the animal (in order to care for it). This is the connotation of the word "Ma'amidin" -- placing the animal in the care of the Nochri.
Rashi makes a similar inference from the word "Pundaka'os." The Mishnah does not prohibit bringing an animal to the home of a Nochri, but rather placing the animal in a Nochri's inn. A Pundak is a place where travelers appoint the innkeeper to care for their animals. This is why Rashi mentions that the innkeeper is being paid; Rashi is emphasizing that the prohibition applies only when the innkeeper is responsible for the care of the animal.
2) AN IDOLATER'S LUST
QUESTIONS: The Gemara says that a Jew may not leave his female animal alone with a Nochri woman, because the Nochri woman often has male friends visiting her who might find the animal and be Rove'a it. According to one explanation of the Gemara, even when the Nochri woman is home, her male friend will prefer the animal over the woman, because Nochrim "have a greater desire for the animals owned by Jews than for their own wives." The reason for this is related to the defilement ("Zuhama") that the Nachash brought upon Chavah when it seduced her to sin. A Jew does not have that Zuhama, since it was removed when the Jews stood at Har Sinai and received the Torah.
(a) Why does a Nochri prefer an animal that belongs specifically to a Jew? Why should there be any difference between an animal owned by a Jew and an animal owned by a Nochri? Since the animals did not receive the Torah, all animals should be the same with regard to Zuhama!
(b) The Chachamim teach that the Zuhama of the Nachash was removed from the Jewish people when they received the Torah at Har Sinai. The Rishonim (TOSFOS CHOCHMEI ANGLIYA, KOLBO (Perush on the Hagadah), TASHBATZ (Avos 3:18)) explain that this is what is meant in the Hagadah of Pesach, "Had Hash-m brought us to Har Sinai without giving us the Torah, it would have been enough." What would we have gained by being brought to Har Sinai without receiving the Torah? The answer is that standing at Har Sinai, even without receiving the Torah, would have accomplished the removal of the Zuhama.
What is the meaning of this Zuhama that overcame Chavah due to her interaction with the Nachash, and how was it removed at Har Sinai?
(a) It seems from the words of TOSFOS CHOCHMEI ANGLIYA that he understands that the Gemara mentions the animal of a Jew only because the Nochri stays away from his own animal because he does not want to cause it to become sterile.
(b) The Rishonim and Acharonim explain that "Zuhama" refers to a heightened level of lust. The Nochri is so overcome with lust that he desires even animals. When the Jewish people stood at Har Sinai and Hash-m revealed Himself to them, the awe of Hash-m weakened their lusts, making their lusts more controllable, and that is how their Zuhama was removed.
Why does the Gemara say that the Nochri "prefers" the animal to his wife? Perhaps it is because of the principle mentioned in the Gemara in Nedarim (91b) of "Mayim Genuvim Yimtaku" (Mishlei 9:17) -- taking what one is not allowed to have provides more physical pleasure.
The words of the RAMBAM (in Moreh Nevuchim 2:30) shed light on the topic of the sin and Zuhama of the Nachash. The Rambam, based on the Midrash, explains that it was not the Nachash that seduced Chavah, but rather it was the Satan who "rode" upon the Nachash who seduced Chavah. This is what the Chachamim mean when they say that the Nachash seduced Chavah and infused her with Zuhama, which remained in her descendants until the Jewish people stood at Har Sinai. This is also what the verse means when it says that man overcomes the Nachash by crushing its head, and the Nachash overcomes man by biting his heel.
What does the Rambam mean by this? The heel alludes to the lowliest and most mundane part of the person (see Tosfos to Nazir 51a, DH Rekev). The Satan seduces a person by attracting him through his physical lusts and desires for worldly pleasures. Man, in turn, must use his head to overcome these lusts. The way that man conquers the Satan is by crushing Satan by his head. The head of the Satan refers to arrogance, which arouses within a person his physical lusts (see Zevachim 88b, which says that the Mitznefes worn upon the head atones for arrogance, and the Tzitz worn upon the forehead atones for brazenness). A man's heel, which represents his lowliness and mundane qualities, can be used for his benefit or for his detriment. If he allows the arrogance of the Satan to fill himself with lust for worldly pleasures, it will bring his downfall. If, on the other hand, his lowliness arouses within himself a sense of modesty and humility in front of the Creator, this humility will enable him to overcome the attempts of the Nachash to seduce him by arousing his arrogance and his desire to sin. (See Berachos 5a, which says that remembering the day of death helps a person avoid sin.)
The Rambam adds that the word "Satan" and the word "Nachash" allude to the qualities of the Satan. Perhaps he means that "Nachash" is related to the word "Nechoshes" (see Rashi to Bamidbar 21:9) which is a metal which represents arrogance and brazenness, as the verse says, "u'Metzchacha Nechushah" (Yeshayah 48:4).
Amalek is referred to as "the head (Reishis) of the nations" (Bamidbar 24:20) because they are like the head of the Nachash; they are the most arrogant of the nations who try to arouse the other nations to sin. That is why they must be destroyed, just as man must crush the head of the Nachash in order to overcome the Satan.
The Zuhama of the Nachash was removed from the Jewish people when Hash-m appeared to the people at Har Sinai. According to the Gemara in Nedarim (20a), the verse (Shemos 20:17) teaches that the purpose of Hash-m's revelation to the Jewish people at Sinai was that they should acquire the trait of bashfulness, which would guarantee their humility and prevent them from sinning. This is what cured the arrogance that the Nachash infused in man.
(See also MESHECH CHOCHMAH, beginning of Vayishlach; TZAFNAS PANE'ACH, end of Hilchos Terumos; PENINIM YEKARIM to Parashas Bereishis; and MALBIM in ERETZ CHEMDAH, Bereishis 2:17, at length.)