Gemara

Question: What is the case of a pit of partners, according to the opinion that obligates only for a pit in Reshus ha'Rabim?

If they asked Levi to dig it, Ein Shali'ach l'Devar Aveirah (he is responsible)!

Answer (R. Yochanan): The case is, they jointly removed the layer of dirt that completed the pit to a depth of 10 Tefachim.

Bava Metzia 10b (Ravina): Ein Shali'ach l'Devar Aveirah only when the Shali'ach is Bar Chiyuva (liable for transgressing).

Question: If so, if Reuven told a (married) woman or a slave to steal, is Reuven liable because they are exempt?!

Answer: Women and slaves are liable, just they cannot pay now. If the slave was freed or the woman became divorced, he or she must pay.

(Rav Sama): Ein Shali'ach l'Devar Aveirah only when the Shali'ach can choose whether or not to comply.

They argue about a Kohen who told a Yisrael 'be Mekadesh a divorcee to me', or a man who told a woman 'cut a boy's sideburns for me.' Rav Sama exempts the Meshale'ach, and Ravina obligates him.

Beitzah 17a - Question: If one did not make an Eruv Tavshilin, is his food forbidden? I.e. must he transfer ownership of it to others before they may cook it?

Answer (Beraisa): If one did not make an Eruv, he may not cook for himself or for others. Others may cook his food only if he is Makneh it to them.

Rishonim

Ran (Beitzah 9b DH Ibo'i): Bahag's text says that if his food is permitted, he may give it to another to cook it. He must be Makneh it, lest the latter be his Shali'ach.

Sha'ar ha'Melech (Hilchos Yom Tov 6:9): This is not difficult for Ravina, who says that Yesh Shali'ach l'Devar Aveirah when the Shali'ach is not Bar Chiyuva. Rava Sama says that Ein Shali'ach whenever the Shali'ach can decide. How can he explain why the Beraisa requires him to give his food? It seems that the Ran holds that Yesh Shali'ach for an Aveirah mid'Rabanan.

Tosfos (Bava Metzia 10b DH d'Omar): Even though a Yisrael Shali'ach who is Mekadesh a divorcee to a Kohen transgresses Lifnei Iver, since he would be exempt if he were Mekadesh her to himself, he is not called Bar Chiyuva.

Poskim

Shulchan Aruch (OC 527:20): If one was not Me'arev, he may not cook for himself or for others. Others who were Me'arev may cook for him only if he gives his food to them for a gift.

Beis Yosef (DH u'Mah she'Chosav Al): Ba'al ha'Itur permits him to cook for others (who made an Eruv). He is like their Shali'ach, and is (permitted) like the Meshale'ach. However, it seems that the Beraisa and Rambam forbid.

Maharit (1:116): It is not clear whether Yesh Shali'ach for an Aveirah mid'Rabanan. Mid'Oraisa, (there is no Aveirah and) he is a Shali'ach. Or, perhaps since mid'Rabanan it is forbidden, 'he should obey the Rav (Hash-m), and not the Talmid'' applies. All mid'Rabanan laws are based on "Lo Sasur." If one transgresses mid'Rabanan laws, others may call him 'a transgressor', and he can be excommunicated.

Mishneh l'Melech (Hilchos Rotze'ach 2:2): Why was the Maharit unsure? The Gemara in Bava Kama says that Ein Shali'ach regarding digging in Reshus ha'Rabim, which is mid'Rabanan!

Rebuttal (Noda bi'Yehudah EH Sof 78 DH u'Milvad): If Levi was permitted to damage Reshus ha'Rabim (and Moshe was hurt), R. Yehudah exempts Levi from paying. If the Torah permits to dig, why does it obligate for one's pit?

Sha'ar ha'Melech (ibid.): In this case, the Shali'ach is commanded not to dig in Reshus ha'Rabim. We cannot learn from here to cooking for one who did not leave Eruv Tavshilin, in which the Shali'ach has no Isur at all. Even Rav Sama agrees that Yesh Shali'ach in such a case of an Aveirah mid'Rabanan. Alternatively, the Ran holds that Ein Shali'ach exempts the Meshale'ach from lashes, but in any case it is forbidden, like the Taz (YD 160:11) says.

Mishneh l'Melech: The Gemara said that Rav Sama and Ravina argue about a man who told a woman 'cut a boy's Pe'os for me.' If Ein Shali'ach even for mid'Rabanan laws, even Ravina would obligate the Shali'ach! Even though the Torah does not forbid a woman to cut Pe'os, mid'Rabanan she may not, even of a minor! It is difficult to say that the Sugya is like Rav Huna, who totally permits a woman to cut a child's Pe'os, for the Halachah is unlike him. Perhaps she is not called Bas Chiyuva for she is liable only mid'Rabanan, whereas the Meshale'ach is liable mid'Oraisa. This requires investigation.

Noda bi'Yehudah (EH 75): Most Poskim permit a woman to cut a boy's Pe'os l'Chatchilah. Even according to those who forbid, it is not difficult to say that the Sugya is like Rav Huna. However, we need not. A woman is forbidden due to the boy's Isur. Even though we need not stop minors from transgressing, we do not cause them to transgress. This is why Chovah (who was cursed for cutting her sons' Pe'os) buried her sons. A woman is not intrinsically commanded. Her Isur is like Lifnei Iver, which does not make her Bas Chiyuva. Why did the Gemara think that a woman is not Bas Chiyuva for theft? Surely she is forbidden! Rather, since she cannot pay, her Chiyuv is less than that of the Meshale'ach, and this is not called Bas Chiyuva.

Noda bi'Yehudah: Surely Ein Shali'ach even for an Aveirah mid'Rabanan, like the Mishneh l'Melech proved. Tosfos said that even though a Yisrael transgresses Lifnei Iver, since he would be exempt if he were Mekadesh her to himself, he is not called Bar Chiyuva. Lifnei Iver is only mid'Rabanan when the transgressor could transgress by himself. If Yesh Shali'ach l'Devar Aveirah mid'Rabanan, why was Tosfos concerned about Lifnei Iver?

Hagahas Baruch Frankel: In one answer, the Ritva (10b DH l'Hach) says that when the Kohen would have been Mekadesh her himself, Lifnei Iver is only mid'Rabanan, so Yesh Shali'ach l'Devar Aveirah. Tosfos rejected this, for the Gemara said Stam, i.e. even when he would not Mekadesh her himself. Presumably he would not Mekadesh her himself, for this is forbidden! In any case, the Shali'ach is liable for Lifnei Iver for making the woman transgress!

Rema (YD 160:16): Some (Rashi) permit David to tell Levi 'lend to me Moshe's money, with Ribis', for the borrower does not give directly to the lender. David and Moshe do not transgress, for Ein Shali'ach l'Devar Aveirah.

Pischei Teshuvah (14): We cannot permit Ribis mid'Rabanan, e.g. through a sale, through a Shali'ach. Perhaps Rashi permits only when the Ribis would be mid'Oraisa, for then Ein Shali'ach! The Maharit was unsure about this.

Note: Mid'Rabanan, one may not be Mekadesh a woman through a Shali'ach (Kidushin 41a). Perhaps Shali'ach l'Devar Aveirah does not apply because it is not an absolute Isur (e.g. we permit if he cannot be Mekadesh by himself).