1) THE PURIFICATION OF THE TRIBES
QUESTION: Rebbi Chama bar Chanina says that Hash-m will begin with the tribe of Levi when He purifies the Shevatim and filters out all of the impure elements of their lineage. He derives this from the verse, "He will sit, smelting and purifying (Metzaref u'Metaher) silver, and He will purify the children of Levi and refine them like gold and like silver, and they will be to Hash-m like those who present an offering in righteousness" (Malachi 3:3).
Rebbi Yehoshua ben Levi understands the verse differently. He explains that it means that Hash-m will purify the Mamzerim and allow them entry into the Jewish people. RASHI explains that Rebbi Yehoshua ben Levi understands that when the verse says that Hash-m will "purify" ("Metaher") the Jewish people, it does not mean that Hash-m will filter out the impurities. Rather, it means that Hash-m will make the impure elements pure and thereby enable them to join the Jewish people.
Rashi explains how Rebbi Yehoshua ben Levi understands the word "Metaher" in the verse, but not how he understands the word "Metzaref" ("smelting") in the verse. "Metaher," purifying, implies making something which is Tamei become Tahor. The definition of "Metzaref," however, is the removal of impurities! How does Rebbi Yehoshua ben Levi explain that part of the verse?
ANSWER: The RAMBAM (Hilchos Melachim 12:3) writes that when the Gemara says that Hash-m will begin with the tribe of Levi when he "purifies" the Shevatim, it means that He will clarify who is a bona fide Kohen and who is a Levi. Those who are not genuine Kohanim and Leviyim, but who were assumed to be Kohanim and Leviyim until now, will join the ranks of the rest of Yisrael. The "purification" of Shevet Levi means that Hash-m will reveal from which Shevet each person truly comes. The "purification" of the tribe does not mean that Hash-m will reveal who is a Mamzer and who is an Eved, because "once they (the impure elements) have become mixed in, they have become mixed in [and are permitted]."
The commentaries point out that the words of the Rambam imply a difference between the members of Shevet Levi (Kohanim and Leviyim) and the rest of Yisrael. The Rambam emphasizes that the lineage of the rest of Yisrael will be clarified ("Meyuchas") only according to their respective Shevatim. Their lineage will not be clarified with regard to their legitimacy; there will be no clarification as to who is a Mamzer and who is an Eved. Rather, "once they have become mixed in, they have become mixed in."
The Rambam implies that the clarification of the lineage of Kohanim requires that they become absolutely genuine and "Meyuchas." Why does this requirement apply only to the Kohanim?
The RIDVAZ explains that this is a special requirement in the Halachos of Avodah, the service in the Beis ha'Mikdash. Although the principle of "once they have become mixed in, they have become mixed in" permits persons of doubtful lineage to marry, an absolutely genuine lineage is necessary in order to perform the Avodah in the Beis ha'Mikdash.
The Ridvaz and others explain the verse quoted by the Gemara according to this approach. "Metzaref" refers to the process that will be done with Shevet Levi, the Kohanim and Leviyim, who must be cleansed of all Pesulim in order to perform the Avodah in the Beis ha'Mikdash. "Metaher" refers to the process that will be done with the rest of Yisrael for the sake of permitting marriages with Pesulim, to whom the principle of "once they have become mixed in, they have become mixed in" applies.
2) THE FUTURE STATUS OF FAMILIES OF DOUBTFUL LINEAGE
QUESTION: Rebbi Yitzchak states that in the future, "Mishpachah she'Nitme'ah, Nitme'ah" -- a family with a Pesul (such as Mamzerus) that became "mixed" and unidentifiable with the rest of the Jewish people will "remain mixed" and be considered part of the Jewish people. Abaye cites a Beraisa which also expresses this principle.
RASHI (DH Tanina) explains that the families of impure lineage "will not be separated or distanced [from the Jewish people], and the doubt about their status will not be clarified... but rather they will be left in their state of doubt and, in the future, they will be Kesherim."
The future time ("l'Asid la'Vo") at which the families of doubtful status will be considered Kesherim will be when Eliyahu ha'Navi comes and declares pure all of the families that have a Pesul intermingled with them. Until that time, they remain in a state of doubt, a state of Safek Kesherim. Since they remain in a state of doubt until the arrival of Eliyahu ha'Navi, why is a person permitted to marry into such a family prior to the arrival of Eliyahu ha'Navi? Such a marriage should be prohibited out of doubt, and one should be permitted to marry into it only once the family's lineage has been declared absolutely pure.
ANSWER: The RAN in the name of the RAMBAN answers with a fundamental rule: Halachah does not change. The Gemara in Berachos (34b) states that all Mitzvos and Halachos that apply nowadays will apply in the times of Mashi'ach as well. The only change will be the end of the subjugation to foreign nations.
The same principle applies inversely. A Halachah that applies in the times of Mashi'ach must also apply nowadays. There will be no addition or elimination of any Halachos. Therefore, if, in the times of Mashi'ach, one will be permitted to marry into a family whose lineage is doubtfully pure, that Halachah must apply nowadays as well. (Although the "Taharah" which Eliyahu ha'Navi will effect does not exist at present, that "Taharah" means that he will permit them, and therefore that Heter must exist now as well.) (A. Kronengold)
3) HALACHAH: ALLOWING FAMILIES OF UNTAINTED LINEAGE TO MARRY FAMILIES OF TAINTED LINEAGE
SUMMARY: The Gemara gives examples of specific families which, in the future, Eliyahu ha'Navi will clarify to be Tahor or Tamei. The Gemara adds that there was another family of impure lineage whose identity the Chachamim did not want to reveal publicly. They revealed the identity of that family only to their sons and students once every seven years (or, according to some, twice every seven years).
Although the Halachah is that "once they have become mixed in, they have become mixed in" (see previous Insight), the application of this principle is subject to three conditions:
1. Only when the original Pesul was not known is a family whose status is in doubt ("Mishpachah she'Nitme'ah") permitted to remain part of (and marry into) the Jewish people, b'Di'eved. If, however, the Pesul was known and they married into the Jewish people anyway (as in the case of Ben Tziyon), that family will be barred from entering the Jewish people in the future.
2. Although one should not reveal the identity of a "Mishpachah she'Nitme'ah," one is permitted -- and even encouraged ("Kasher ha'Davar," as the REMA writes) -- to give over such information to "Tzenu'in" (for the purpose of knowing which families to refrain from marrying). This may be inferred from the fact that the Chachamim used to reveal the identities of these families to their students at certain intervals in order to enable the "Tzenu'in" to refrain from marrying such families. This was not done in public, however, lest rumors circulate about the family's status as Pasul, since, in practice, marriage with them is permitted. (The reason given by the RAN, that "the Shechinah does not dwell" among such families, still applies.)
3. The only time a family's Pesul may not be revealed is after the family in question has married into Tahor families. If, however, no one from the Pasul family has married yet into a Tahor family, whoever has information about the family's Pesul is required to reveal it to others. This requirement is inferred from the Halachah of "once they have become mixed in, they have become mixed in," which implies that the family may remain married to a Tahor family only b'Di'eved (once they have already married), but l'Chatchilah such a family is not permitted to marry into a Tahor family. (See REMA EH 2:5.)