1) THE OFFSPRING OF A FEMALE SHEEP AND A MALE GOAT
QUESTION: Rebbi Oshiya taught a Beraisa in which Rebbi Meir and the Chachamim argue about a case of a sheep born to a goat, or a goat born to a sheep. The Gemara suggests that the Beraisa is discussing a case of a goat born to a female sheep and a male goat, or a lamb born to a female goat and a male sheep. Rebbi Meir and the Chachamim disagree about whether the offspring is considered to be related to its father. Rebbi Meir maintains that we take into account the father, and thus the offspring is considered to be related to its father, and if one slaughters the father and the child on the same day, he transgresses the Isur of "Oso v'Es Beno" (Vayikra 22:28). The Chachamim maintain that we do not take into account the father, and thus the offspring is not considered related to the father and is not subject to the Isur of "Oso v'Es Beno."
According to this explanation, the argument involves only the relationship between the father and its offspring. Why, then, does the Beraisa mention the fact that the mother was a sheep or a goat? The species of the mother is not relevant to the argument at all!
ANSWER: TOSFOS (DH b'Rachal) explains that even according to this explanation of the argument, the Beraisa needs to mention the species of the mother. The Beraisa is teaching that even though the father's contribution effects a change in the offspring's appearance (making it look like a goat rather than like its mother's species, a sheep), the Chachamim still do not take into account the contribution of the father.

17b----------------------------------------17b

2) MAKING THE "SHEMIN HA'MISHCHAH" WITH PRECISE MEASUREMENTS
QUESTION: The Mishnah (17a) discusses a case in which a sheep gives birth (for the first time) to twin lambs whose heads emerge from the mother simultaneously. Rebbi Yosi ha'Glili rules that both lambs have the status of the Bechor and must be given to the Kohen. The Rabanan argue and maintain that it is impossible for both lambs to emerge simultaneously -- "Iy Efshar l'Tzamtzem." One lamb must have emerged first and is the sole Bechor. The owner, therefore, must give only one animal to the Kohen, and he keeps the other animal.
The Gemara relates that it was taught in Rebbi Yanai's Yeshiva that according to Rebbi Yosi ha'Glili -- who maintains that perfect precision can occur in natural events (such as twin lambs being born simultaneously) -- perfect precision certainly can be obtained in human actions, where one's deliberate intention guides the outcome of the action.
The Gemara continues and says that even though the Rabanan maintain that perfect precision cannot be achieved in natural events, perhaps they say this only because there is no deliberate intention guiding them. Perhaps they agree that in the actions of humans, it is possible to achieve perfect precision, since there is deliberate intention guiding the outcome of the action.
There seems to be an obvious proof in the Torah that it is possible to achieve perfect precision in human actions. The Torah (Shemos 30:32) prohibits the preparation of the Shemen ha'Mishchah for any purpose other than for anointing the Mishkan, but this prohibition applies only when one prepares it with the exact measurements that the Torah commands to be used in the Mishkan. RASHI there writes that if one uses more, or less, of the amount of an ingredient specified by the Torah, he does not transgress the prohibition.
This seems to prove that it is possible to achieve precision in human actions, because if it was "Iy Efshar l'Tzamtzem," then it would be impossible to transgress the prohibition against preparing the Shemen ha'Mishchah for mundane purposes. One would never be able to put the exact measurement into the mixture, and thus one would always be exempt.
Why does the Gemara not mention this proof?
ANSWER: The MINCHAS CHINUCH (#109) answers as follows. Even if it is "Iy Efshar l'Tzamtzem" in human actions, the prohibition against preparing the Shemen ha'Mishchah still applies. If "Iy Efshar l'Tzamtzem" applies to preparing the Shemen ha'Mishchah, then not only is it impossible to transgress the Isur of making the Shemen ha'Mishchah for mundane purposes, it should also be impossible to prepare the Shemen ha'Mishchah for the anointing of the Mishkan! One cannot suggest that the preparation of the Shemen ha'Mishchah for the Mishkan was accomplished through the assistance of a miracle, because the Torah does not give Mitzvos that can be fulfilled only through the assistance of a miracle.
Rather, it must be that since "the Torah was not given to Mal'achei ha'Shares" (Berachos 25b, Yoma 30a, Me'ilah 14b), whenever the Torah commands that a Mitzvah be performed with a specific weight or measurement, the Torah intends that the Mitzvah be performed according to human capability. If a person performs the Mitzvah as accurately as he can, then he fulfills the Mitzvah. Accordingly, when a person prepares the Shemen ha'Mishchah to the best of his ability, the Shemen ha'Mishchah may be used for the Mishkan. Similarly, if he prepares it to the best of his ability for a mundane purpose, then he transgresses the Isur.
The Minchas Chinuch writes that the Gemara here teaches this principle. The Gemara attempts to prove that for human actions it is possible to achieve perfect precision from the Torah's command to construct the vessels in the Beis ha'Mikdash with exact measurements. This demonstrates that the Torah assumes that human actions can achieve perfect precision.
The Gemara refutes this proof, arguing that when the Torah commands the construction of the vessels with exact measurements, it commands only to make every effort to meet those measurements; the Torah does not expect a person to achieve perfect precision. The Minchas Chinuch explains that this is because the Mitzvos of the Torah were given to man according to his capabilities.
In contrast, when two lambs are born simultaneously, this is not the inevitable way that babies are born. In such a case, the Rabanan maintain that it is "Iy Efshar l'Tzamtzem." When the Torah commands the owner to give the Bechor to the Kohen, it is not referring to such a case. Similarly, when the Torah gives the Mitzvah of Eglah Arufah, it is not referring to a case in which a corpse is found exactly between two cities. The Mitzvah applies to a case in which the corpse is found closer to one city than to any other city. Therefore, in such a case the Rabanan maintain that the rule of "Iy Efshar l'Tzamtzem" applies. (See also KEHILOS YAKOV.) (D. BLOOM)
3) "ALL OF THIS IS IN WRITING BY THE HAND OF HASH-M"
QUESTION: The Rabanan in the Mishnah maintain "Iy Efshar l'Tzamtzem" with regard to natural events -- it is impossible for two natural events to occur simultaneously (such as for two lambs to be born to the same mother at exactly the same moment). The Gemara says that even though the Rabanan maintain that perfect precision cannot be achieved in natural events, perhaps they say this only because there is no deliberate intention guiding them. Perhaps they agree that in the actions of humans, it is possible to achieve perfect precision, since there is deliberate intention guiding the outcome of the action.
The Gemara attempts to prove that the Rabanan agree that for human actions it is possible to achieve perfect precision from the Torah's command to construct the vessels in the Beis ha'Mikdash with exact measurements. This demonstrates that the Torah assumes that human actions can achieve perfect precision.
The Gemara refutes this proof, arguing that when the Torah commands the construction of the vessels with exact measurements, it commands only to make every effort to meet those measurements; the Torah does not expect a person to achieve perfect precision.
The Gemara then cites the verse, "All of this is in writing by the hand of Hash-m, Who gave me understanding to know" (Divrei ha'Yamim I 28:19), which relates how David ha'Melech informed his son, Shlomo, that the plans for the Beis ha'Mikdash were given by Hash-m.
Why does the Gemara quote this verse here? What is the Gemara trying to prove from the verse? It does not seem to be related to the Gemara's discussion at all.
ANSWERS:
(a) RASHI (DH ha'Kol) writes that this verse does not belong in the text of the Gemara and should be omitted.
(b) RABEINU GERSHOM writes that this verse is proof for the Gemara's assertion that when the Torah commands that the vessels are to be built with exact measurements, it is commanding only to try to achieve exact measurements. If the exact measurements are not achieved, the vessels nevertheless become sanctified. The Gemara quotes the verse in Divrei ha'Yamim to prove this assertion.
Rabeinu Gershom, however, does not explain what the proof is from the verse. Perhaps the verse in Divrei ha'Yamim teaches how to interpret the verses in the Torah. The verse in Divrei ha'Yamim teaches that since a blueprint of the Beis ha'Mikdash and its vessels, bearing the descriptions of the measurements of the Beis ha'Mikdash and all the holy vessels, was passed down by the prophets, we may rely on the tradition that the measurements do not have to be perfectly exact.
(c) The BRISKER RAV explains that although the Gemara says that the measurements do not need to be exact, this answer applies to the dimensions of the building and to all of the vessels except the Mizbe'ach. The Mizbe'ach must be exact in its dimensions, as the RAMBAM writes (Perush ha'Mishnayos to Midos 3:2). The Gemara therefore quotes this verse to teach that the Mizbe'ach indeed was built with perfect precision through Ru'ach ha'Kodesh, as the Midrash (see RASHI to Erchin 10b, DH Al) derives from this verse.

OTHER D.A.F. RESOURCES
ON THIS DAF