1) HALACHIC RULINGS OF ELIYAHU HA'NAVI
QUESTION: The Gemara relates that Rabah bar Avuha found Eliyahu ha'Navi in a Beis ha'Kevaros of Nochrim. Rabah bar Avuha asked him whether or not the Halachah follows the view that "Mesadrin l'Ba'al Chov" (a creditor must leave certain basic necessities for a debtor when he collects his debt from the debtor's assets). Eliyahu ha'Navi answered that a Gezeirah Shavah from Erchin teaches that the Halachah is that "Mesadrin l'Ba'al Chov."
The Gemara implies that Halachic rulings of Eliyahu ha'Navi are relevant and acceptable. This is apparent from the Gemara in Eruvin (43a), which discusses whether or not Eliyahu taught certain Halachos, and in Berachos (3a), where Rebbi Yosi learned a number of Halachos from Eliyahu. The Gemara in several places leaves certain Halachic questions in doubt "until Eliyahu comes to resolve them for us" (see, for example, Sanhedrin 44a and Menachos 32a).
How can these Gemaras be reconciled with the teaching of RASHI (Shabbos 108a) that the Rabanan cannot rely on Eliyahu ha'Navi for Halachic questions of Isur v'Heter, but only for the clarification of facts? Moreover, the Gemara in Temurah (16a) teaches that the Rabanan do not rely on a prophet even to remind them of a Halachah l'Moshe mi'Sinai that was forgotten. This seems to be based on the Gemara earlier in Bava Metzia (59b) which teaches that even if a Bas Kol emanates from Shamayim and declares the Halachah to be in accordance with a particular opinion, the Halachah does not follow the Bas Kol because "Lo ba'Shamayim Hi" (Devarim 30:12).
Another difficulty is that the SEFER HA'CHINUCH (#350), the RAN, and the NIMUKEI YOSEF cite the GE'ONIM who rule that "Mesadrin l'Ba'al Chov," and they explain that the reason for the Ge'onim's ruling is that Eliyahu ruled in accordance with the view of "Mesadrin." How can the Halachah follow a ruling issued by Eliyahu ha'Navi? (MAHARATZ CHAYOS here; see also BIRKEI YOSEF OC 32:4.)
ANSWERS:
(a) The MAHARATZ CHAYOS explains that when Eliyahu gives a reason and a source for his ruling, his ruling is no different from the ruling of any other of the Chachamim of the generation.
The MAHARATZ CHAYOS in Berachos (3a) adds that when Eliyahu ha'Navi (or any other prophet) teaches a Halachah as a prophecy, or Nevu'ah, from Hash-m, it is not accepted as authoritative. However, when he teaches the Halachah as his personal opinion of Da'as Torah, then it may be accepted. When Rashi in Shabbos says that Eliyahu cannot teach a Halachah, he means that Eliyahu cannot teach Halachos as Eliyahu ha'Navi -- in his capacity as a prophet. However, he may teach Halachos in his role as a Chacham. (See also BIRKEI YOSEF loc. cit., TORAH TEMIMAH to Vayikra 27:216, and CHASAM SOFER, Teshuvos 6:98, as cited by the DEVAR YAKOV here.)
Similarly, the TOSFOS YOM TOV in Eduyos (8:7) explains that Eliyahu's future rulings will be able to resolve Halachic questions because he will give his reasoning and proofs for his rulings.
(b) Similarly, when Eliyahu merely relates a Halachah that was taught already by someone else, it certainly is accepted. Only when he, as a prophet, teaches a Halachah that was never taught is it not accepted. (See also Insights to Eruvin 43:3.)

114b----------------------------------------114b

2) ELIYAHU HA'NAVI'S RESURRECTION OF THE DEAD
QUESTION: The Gemara (114a) relates that Rabah bar Avuha found Eliyahu ha'Navi in a Beis ha'Kevaros of Nochrim. Rabah bar Avuha asked Eliyahu how he could be in a Beis ha'Kevaros, as Eliyahu was a Kohen and a Kohen is prohibited from entering a Beis ha'Kevaros. Eliyahu answered that the graves of Nochrim have no Tum'ah.
If Eliyahu ha'Navi was a Kohen, then how was he permitted to resurrect the son of the widow by touching him, as described in Sefer Melachim I (ch. 17)? (Rishonim)
ANSWERS:
(a) TOSFOS (DH Amar Lei) answers that since Eliyahu was certain that he would succeed in resurrecting the child, it was a case of "Piku'ach Nefesh" which overrides the prohibition for a Kohen to become Tamei.
Tosfos' answer is difficult to understand. The Halachah of "Piku'ach Nefesh" overrides Isurim only with regard to saving the life of a person who is still alive. There is no indication that one may transgress an Isur in order to bring back to life someone who has already died.
(b) TOSFOS RABEINU PERETZ (cited by the Shitah Mekubetzes) answers that perhaps the child did not actually die, but was merely unconscious (see also TARGUM YONASAN). Tosfos Rabeinu Peretz infers this from the verse that says, "... until there was no more breath left within him" (Melachim I 17:17).
This answer is problematic in light of another verse. The verse in Melachim II (2:9) says that Elisha requested from Eliyahu that he bestow upon him twice his strength. The Gemara in Sanhedrin (47a) explains that Elisha requested from Eliyahu the power to resurrect two dead people, while Eliyahu had resurrected only one. The person that Eliyahu resurrected was this child of the widow (see Rashi there, DH Na Pi Shenayim). The Gemara there implies that the child of the widow was actually dead.
Tosfos Rabeinu Peretz challenges his own answer from another source. Reish Lakish (in Nazir 43a) maintains that a Kohen is not permitted to touch a Goses, a person on his deathbed. The unconscious child was certainly no better than a Goses. How, then, was Eliyahu permitted to touch him? Tosfos Rabeinu Peretz answers that a Goses, according to Reish Lakish, is considered to be dead already since he certainly is going to die. Since this child was going to be revived, he did not have the status of a Goses whom a Kohen is prohibited to touch.
(c) RABEINU BACHYE (Parshas Pinchas, end of 25:11) says that the woman (Ishah ha'Tzarfatis) was a Nochris, and her dead son therefore had no Tum'as Ohel. Even though the corpse of a Nochri does have Tum'as Maga, it could be that Eliyahu did not actually touch the child but rather bent over him without touching him.
The RIDVAZ refutes this answer, citing the Chachamim who say that the child resurrected by Eliyahu was the prophet Yonah ben Amitai, who was a Jew. (Tosfos (114a-b, end of DH Mahu) says in the name of a Midrash that the child resurrected by Eliyahu was Mashi'ach ben Yosef.) The Ridvaz says further that it is not reasonable that such a miracle would have occurred for a Nochri. Moreover, Eliyahu certainly would not have lodged in the home of a Nochris.
(d) The RIDVAZ (Teshuvos 6:203) cites and rejects a number of answers to this question. He concludes that Eliyahu's basis for becoming Tamei was a "Hora'as Sha'ah" that was issued at that specific time permitting him to become Tamei in order that a Kidush Shem Shamayim be achieved through him. This is also the answer of the TOSFOS HA'ROSH.
3) RETURNING A "MASHKON" TO AN "ASHIR"
QUESTION: The Gemara derives from the verse, "v'Im Ish Ani Hu..." (Devarim 24:12), that only when the debtor is poor is a creditor obligated to return the object of collateral at the end of each day. If the debtor is wealthy, the creditor does not have to return the object.
The TOSFOS HA'ROSH and TOSFOS RABEINU PERETZ question this ruling of the Gemara from the Sifri (to Devarim 24:12) which states, "We would have understood [that one is obligated to return a Mashkon each day] only to a poor person. How do we know [that this obligation applies to] a wealthy borrower as well? The Torah says the extra words 'v'Im Ish' in order to include a wealthy man as well." (According to the Sifri, the reason the verse specifically mentions a poor person is that when the borrower is poor, the creditor is punished more severely when he does not return the Mashkon.)
How can this Sifri be reconciled with the Gemara here, which says that one does not have to return a Mashkon to a wealthy borrower?
ANSWER: The TOSFOS HA'ROSH and TOSFOS RABEINU PERETZ answer that the term "Ashir" (wealthy person) has two different connotations. When the Gemara refers to an "Ashir," it refers to a person who is not wealthy in the normal sense, but rather is "wealthy" only with regard to the specific object that was taken as a Mashkon; that is, he has another object of this type and has no need for the one that was taken as a Mashkon. Since he does not need the object that was taken as a Mashkon, the creditor is not obligated to return it to him.
The Sifri, on the other hand, refers to a borrower who is rich, but who does not have another object similar to the collateral. In such a case, the creditor is obligated to return the object to him each day, despite the fact that he is rich. This is also the explanation of the RAMBAN (to Devarim 24:12), who defines an "Ani," a poor person, as one who does not have two of the same object.
(The ME'IRI, however, seems to learn that the Gemara here argues with the Sifri. He writes that when the borrower is wealthy, even if he has only one such object and he needs it, the creditor does not need to return it to him.)
This answer is cited by the SHULCHAN ARUCH (CM 97:20). The VILNA GA'ON there (Hagahos ha'Gra 97:62) cites further proof to this answer from the Mishnah earlier (113a) which does not differentiate between a rich borrower and a poor borrower, but rather between a borrower who has only one object and a borrower who has two objects.