The Gezera Shavah has to have been received from Har Sinai. See Gemara Pesachim 66a (3 lines from bottom) that a person cannot learn a Gezera Shava on his own, and see Rashi there DH veKi that he must have learnt it from his teachers and they in turn heard it from the chain of tradition that goes right back to Mount Sinai. Therefore, whenever a person would say that he received a Gezera Shava from his teacher, we could in turn ask where his teacher heard it from and we would have to list the entire Masorah back to Moshe Rabeinu. It would take a long time to do this every time we cite a Gezera Shava. Instead, Chazal knew that for the accepted Gezera Shavos mentioned in the Gemara, they possessed a tradition which had not only been received by one Sage, but had been transmitted by many Sages who throughout the course of the generations all heard it from their teachers. On the contrary, if the Gemara was always to mention only one Tana or Amora as the source, this might be a sign of weakness, because it would suggest that only this Chacham knew the Gezera Shava. This would be surprising if it really came from Har Sinai.

Wishing you a Gmar Chasimah Tovah

Dovid Bloom

For a gezera shava one does not bring Geula to the world by mentioning who said it, and one does not have to try and trace it back to Moshe Rabeinu:-

I discussed this question with a Talmid Chacham and he made a couple of observations:-

(a) Pirkei Avos 6:6 states that anyone who says something in the name of the source who said it, brings redemption to the world, as we learn from Ester who said to the King in the name of Mordecai. The question is ahy does thsi idea not seem to apply to a Gezera Shava?

(b) The Talmud Yerushalmi states in the first chapter of Maseches Shabbos, on the second Mishnah (page 12 in the more standard edtions with Pnei Moshe and Korban Ha'Eida) in the name of Rabbi Yochanan that if one can trace back the chain of tradtion to Moshe Rabeinu do so, and if not, then mention either the first of the chain, or the last of the chain. Again, this does not seem to be put into practice in connection with Gezera Shava.

(c) I suggest an answer to these 2 questons on the lines of what I wrote above. The point is that a Gezera Shava is different from other Dinim of the Torah. If a gezera shava does not originate from Moshe then it is worthless. Therefore whenever we find a Gezera Shava in the Gemara this means that Chazal must know that it possesses a strong tradition, so the very fact that it is mentioned in the Gemara means that Chazal are confident that that it does go back to Sinai even if we cannot actually specify the chain. The very fact that this Gezera Shava has not been challenged in previous generations proves that it is fully accepted, and it is not necessary to trace it back.

Dovid Bloom

The rule of Nazir 56b does not apply to Gezera Shava:-

1) Bavli Nazir 56b states that when one says a Halacha in the name of several chronological sources, one says the first and the last sources but not the middle ones. The Gemara proves this from a Mishnah where Nachum HaLabler said that he received a Halacha about Peah from Rav Miyasha; who received it from Abba; who received it from the "Pairs"; who received it from the Prophets; who received it Halacha from Moshe on Sinai. The Gemara points out that Yehoshua and Kalev are absent from this list, which proves that one omits middle names.

2) We must say that the Gemara would not mention a long chain of Chachamim; in the way that it did in the above Gemara; if a Gezera Shava was involved. This is because there is a difference between a Halacha for Peah; for instance; and a Gezera Shava. This is because a Halacha about Peah does not have to be from Sinai, so in cases where it is we stress the special authority of this Halacha. In contrast a Gezera Shava must always be from Sinai (see Rashi Nidah 19b DH Ein that it must be Halacha LeMoshe MiSinai) so it is not necessary to trace it back, because if it would not have been well-known to Chazal that it was reliable they would not have accepted it.

Dovid Bloom

The Tzedukim confused the Chachamim by inventing Gezera Shavos:-

I found, bs'd, a fascinating explanation by one of the Rishonim; in Chidushei Rabeinu Yehonasan of Lunil on Kidushin end 35b. I am sure the gezera shava chabura will find this very interesting, and I think it might also help us to answer our question.

Rabeinu Yehonasan is discussing the Gezera Shava "Korchah Korchah" mentioned in Kidushin 36a. He writes that Rabanan disagree with this Gezera Shava. R. Yehonasan writes that one should not be amazed whenever we find that there is a dispute concerning a Gezera Shava; that we know that a person cannot learn a gezera shava unless he heard it from his teacher; and his teacher from his teacher; right back to Har Sinai. R. Yehonasan writes that before the Baytusim and the Tzedukim rose up and denied the Oral Torah, no-one could find a Gezera Shava unless it was correct, clear, pure and familiar to everyone, with nobody disagreeing. Then the Tzedukim and Baytusim came along, and mislead the Chachamim by inventing their own Gezera Shavos and teaching them to their followers, who in turn taught them to their followers. When the Sages perceived what was happening they instituted that no-one may pay attention to a Gezera Shava unless it is familiar to the majority of the Chachamim. If only an individual is familiar with a Gezera Shava, one should ignore it.

I suggest that we can now answer why Chazal do not trace back the origin of a Gezera Shava. This is because the Saducees might spread false rumours about different Chachamim who they claimed had given a Gezera Shava. The way to fight against the fakers is not to cite the names of sources. Rather, what is required is a general consensus, amongst those who believe in Torah She-Baal Peh, that this Gezera Shava is accepted by the Perushim. One requires a reliable "grapevine" of Yerai Shamayim Sages who have checked out thoroughly which are the genuine Gezera Shavos.

Dovid Bloom

R. Yehonasan of Lunil explains why; both before and after the time of the Tzedukim; it would not be in place for the Gemara to state who is the Man deAmar for a Gezara Shava;-

Looking again at what I wrote above, I think I have not done justice to the way we should explain the words of a Rishon.

1) If we look carefully, we see that R. Yehonasan of Lunil writes that after the Tzedukim made all the problems that they made, Chazal made a Takana that one should not be concerned about a Gezera Shava unless it is in the mouths of the majority of the Chachamim. If the Gezera Shava was said only by an individual, one should not pay attention to it.

This answers directly our question. If the Gemara were to say who said the Gezera Shava, this would; on the contrary; be a sign of weakness. because it would suggest that only this Chacham said the Gezera Shava, and if so, one would have to reject it. One can only use a Gezera Shava if the majority of the Chachamim in the time of the Gemara accept it, and it clearly would not be possible to cite so many names every time we mention a Gezera Shava.

[In this way, a Gezera Shava is very different than other Halachos of the Torah. With other Halachos we often find that the Gemara cites a Halacha in the name of one Tana or Amora, and then the Gemara asks questions on this Halacha and if we manage to deflect the challenges to the Halacha we can say that it is accepted. So it is not a sign of weakness if the Halacha starts off as a single opinion, whilst for a Gezera Shava the latter is a reaaon for rejection].

2) Concerning the Gezera Shava prior to the period in history when the Tzedukim caused problems, we notice that R. Yehonasan writes that any genuine Gezera Shava was, at that time, "correct, clear and pure in everyone's mouths". Again, this, means there would be no need to mention the source of the Gezera Shava because everyone agree with it.

Dovid Bloom