(1) Your question can be answered with the help of another question raised by the Gevuros Ari (written by the author of the Sha'agas Aryeh) in our Sugya DH Asur. He asks on the Gemara that certain Cohanim are forbidden all year round to drink wine, from the Gemara Rosh Hashana 11a which cites a dispute between R. Eliezer and R. Yehoshua whether the redemption is going to happen in Nissan or Tishri. Gevuros Ari asks therefore that it should be sufficient to ban drinking wine only for these 2 months, so why is it necessary to ban it for the entire year?

GA answers on the basis of the Talmud Yerushalmi Maaser Sheni 5:2 that the Beis Hamikdash will be built before the Mashiach from the House of David comes. He writes that according to this there is no fixed day for the building of the Beis Hamikdash - it could be built any day of the year. In contrast R. Eliezer and R. Yehoshua discuss when the Mashiach will come, which can only be in these months.

Similarly, one can answer your question about Eliyahu HaNavi by saying that Eliyahu will come before the Mashiach comes, but the Beis Hamikdash will be built before that, so Eliyahu will not be able to help us to know when the B.H. will be built.

I found your question about the sfek sfeika very difficult but I am going to have a quick try at answering it for the time being.

I saw in Aruch l'Ner to Sanhedrin 22b (where our Sugya also comes up) DH Michlal that he cites a Gemara in Yevamos 101a - in fact it seems to be more explicit in the mishnah there 100b - that if a Cohen does not know which Beis Av he belongs to, he is entitled to serve in the Beis Hamikdash on any day he wishes. Mishnah Yevamos 100a discusses someone who does not who his father is (because his mother did not wait 3 months after her first husband died before re-marrying). The mishnah 100b states that if both husbands were Cohanim the son now has a problem because he does not know which Beis Av his father belonged to. In such a case he can however serve in the BH on either day but will not receive meat from the sacrifices from either day.

One sees from this that a Cohen who does not know which Beis Av he belongs to can work any day he likes. Therefore one can argue that the sofek here that the Cohen does not know which Beis Av he belongs to, is not a sofek which would stop him serving in the Beis Hamikdash, so only one sofek remains :- that maybe the moshiach will not come today.

However the above is only a possible suggestion, and your question requires further study.

[By the way I found that the answer that I gave to question (1) is very similar to what the Minchas Chinuch 152:9 writes, Boruch She-kivanti].

May we be zoche that the Beis Hamikdash will be built today (we say in the Nachem prayer in Mincha of Tisha b'Av that Hash-m Himself will build it with fire - see Rashi Sukah end 41a that it will come down from Heaven) and that this year Tisha b'Av will be a Yomtov!

(2) I found your question about the sfek sfeika very difficult but I am going to have a quick try at answering it for the time being.

I saw in Aruch l'Ner to Sanhedrin 22b (where our Sugya also comes up) DH Michlal that he cites a Gemara in Yevamos 101a - in fact it seems to be more explicit in the mishnah there 100b - that if a Cohen does not know which Beis Av he belongs to, he is entitled to serve in the Beis Hamikdash on any day he wishes. Mishnah Yevamos 100a discusses someone who does not who his father is (because his mother did not wait 3 months after her first husband died before re-marrying). The mishnah 100b states that if both husbands were Cohanim the son now has a problem because he does not know which Beis Av his father belonged to. In such a case he can however serve in the BH on either day but will not receive meat from the sacrifices from either day.

One sees from this that a Cohen who does not know which Beis Av he belongs to can work any day he likes. Therefore one can argue that the sofek here that the Cohen does not know which Beis Av he belongs to, is not a sofek which would stop him serving in the Beis Hamikdash, so only one sofek remains :- that maybe the moshiach will not come today.

However the above is only a possible suggestion, and your question requires further study.

[By the way I found that the answer that I gave to question (1) is very similar to what the Minchas Chinuch 152:9 writes, Boruch She-kivanti].

Kol Tuv

Dovid Bloom

(1) The reason the Cohanim cannot rely on Eliyahu HaNovi to come in advance and announce the Moshiach's coming is because the Gemara in Eruvin 43b states that when he comes he will go to the Great Beis Din, so not everyone will know immediately that he has arrived (the Gemara does not say that he will arrive 3 days before the moshiach as you wrote, but rather only 1 day) and consequently the Cohanim will not know about the Moshiach coming, in time to stop drinking.

See Rosh Hashanah 31b that the redemption will take place from Tiverya. It appears from the Rambam Hilchos Sanhedrin 14:12 that the Great Beis Din will also start up again in Tiberias. So if Eliyahu will arrive in Tiverya, the Cohanim in Yerushalayim might not know in time.

(2) The reason why one cannot rely on a sfek sfeka is because if one is able to find out whether one of the doubts is a real doubt, one does not use a sfek sfeka. This is stated by the Shach YD 110, Laws of Sfek Sfeka #35, that where it does not cost money to clarify one of the doubts, one does not rely on a sfek sfeka.

Therefore, in our Sugya, the Cohen can find out which Beis Av he belongs to. Especially according to the Meiri here, who learns that the Sugya refers specifically to the times when the Beis Hamikdash stood, it should not be difficult for the Cohen to verify on which day his forefathers served in the Beis Hamikdash.

KOL TUV

Dovid Bloom

P.S. We have another Mazeltov because another son of ours got engaged!

The Ritva in Eruvin 43b writes that when the Gemara states there that Eliyahu will go to the Great Beis Din this means he will go to the Lishkas HaGozis, the place in the Beis HaMikdash where the Sanhedrin convened. The Ritva appears to stress that Eliyahu will go to the "place" of the Great Beis Din i.e. the Beis Din will not yet have been set up, but Eliyahu will be initially revealed at this place.

Even though the Cohanim in the Beis Hamikdash will therefore know immediately that Eliyahu has arrived and that the Mashiach is coming and will be able to stop drinking wine in time, nevertheless the problem will be with all the other Cohanim in the world, who are not nowadays to be found in the vicinity of the Beis Hamikdash. They may not know in time that the Mashiach has arrived (because the Mashiach will only appear at the Great Beis Din, not anywhere else), so all the other Cohanim might find out too late that it is time for them to serve in the Beis Hamikdash, which they will not be able to do in time, because they have been invalidated by drinking wine.

Kesivah u'Chasimah Tovah

Dovid Bloom

I had a question on the follow-up answer that I wrote above to question (2). The question is from Rema Shulchan Arukh YD 110:9, at end, which states that if one has a sfek sfeka, then even though one could verify the matter, one is not obliged to do so. Even though I quoted above a Shach who disagrees with Rema, nevertheless the Shach himself writes that one only must check it if there is no loss involved.

Now, Rashi 17a DH Cohen writes that our Sugya applies nowadays - i.e. after the destruction of the Beis Hamikdash. In addition, Rabeinu Chananel writes at top 17b, that according to Rabanan the Cohanim were forbidden to drink wine also in the times of Abaye and Rava, who lived hundreds of years after the destruction of the Temple, by which time it must have been very difficult to find out which Beis Av each Cohen emanated from. Great difficulty involved in checking can be considered equivalent to incurring a loss through checking, so according to this, everyone should agree that one is not required to check.

The answer to my question is that we must understand slightly differently this idea that if the sfek sfeka can be verified one cannot be lenient. What we mean is that if the sfek sfeka will certainly become verified automatically later on, then one cannot be lenient and rely on the sfek sfeka.

I found this svara in Sdei Chemed (who writes at great length concerning sfek sfekos. The idea I found is under the entries for letter "Samech" #29. He writes that even if something that cannot be verified now, but only a long time afterwards, one must nevertheless be stringent on this, and not be lenient with a sfek sfeika. Sdei Chemed writes that since it may in future transpire that this matter is forbidden, how is it possible to permit it now?

So, when the Beis Hamikdash will be built, speedily in our days, it will certainly become known then exactly to which Beis Av each Cohen belongs. How then is it possible now for a Cohen now to drink wine, since it might be built tomorrow and it will later on be known to everyone that tomorrow is the day of this Cohen to serve in the Beis Hamikdash, but he was not able to do so because he had drunk wine?!

KOL TUV

Dovid Bloom