Gemara

88b - Question: What do we learn from "Es Kol ha'Kelim ha'Eleh"?

Answer: This teaches that they must be made of gold.

Question: It explicitly says that they are of gold - "v'Asisa Es Neroseha...u'Malkacheha u'Machtoseha Zahav Tahor"!

Answer: "Es Kol ha'Kelim ha'Eleh" teaches about the mouths of the lamps. One might have thought, since they become black due to the flame, the Torah would be concerned for money of Yisrael and would not require making them of pure gold (some texts - of gold);

The verse teaches that also they must be made of (pure) gold.

Chulin 9a (Rav Huna): We assume that a slaughtered animal is permitted, unless we know that it was a Tereifah.

11b - Question (Rav Kahana or Rav Simi): Perhaps we follow the majority only there is no alternative!

Support: If you would not distinguish, according to R. Meir, who is concerned for the minority, it should be forbidden to eat meat (lest the animal had a hole where it was slaughtered)!

R. Meir cannot (totally) forbids eating meat, for we are commanded to eat Korban Pesach and Shelamim! Rather, he follows the majority when there is no alternative. Perhaps also Chachamim follow the majority only when there is no alternative!

Chulin 110b: Abaye sent Rav Safra to ask (in Eretz Yisrael) if liver may be cooked (in water).

Rav Safra: Rav Zerika cooked liver for R. Ami, and he ate it.

Abaye: I knew that the liver itself is permitted. I asked whether it forbids what it is cooked with.

Rav Safra: The same Mishnah that permits the liver itself, also forbids what it is cooked with!

(Mishnah): Liver forbids what it is cooked with, but it itself remains permitted, because it emits (blood), but does not absorb.

Abaye: Perhaps only a forbidden liver (e.g. of a Tereifah) forbids other food because it emits forbidden fat, but a permitted liver does not forbid (due to blood) or become forbidden!

Rav Zerika (to Rav Sfara): Yehudah brei d'R. Shimon ben Pazi served the branch holding the heart, lungs and liver to me and to Yanai brei d'R. Ami; and we ate it.

Question (Rav Ashi): Perhaps the opening of the branch was outside the pot (so the blood flowed out), or the liver had previously been Nichlat (treated so it would not emit blood when cooked)!

Rav Huna would put liver in vinegar (to be Cholet it). Rav Nachman would put boiling water over it.

Rav bar Sheva visited Rav Nachman. He was served overcooked liver. He would not eat it. When Rav Nachman heard about this, he commanded that they force him to eat it.

Tana'im argue about this:

(Beraisa - R. Eliezer): The liver forbids, but does not become forbidden, because it emits (blood), it does not absorb;

R. Yishmael, son of Yochanan ben Brokah says, if liver is seasoned with spices or overcooked, it forbids and becomes forbidden.

Rabah bar Rav Huna visited Rabah bar Rav Nachman's house. He noticed that chambers of the liver had absorbed blood. He said that they should avoid this. I.e. they should cut it lengthwise and widthwise, and roast it with the cut side on bottom.

Rishonim

Rif (Chulin 39b): The Gemara concludes that one may cook liver after Chalitah in vinegar or boiling water. However, the Yeshivos said that we do not know how to do this. We are stringent about Safek Isur. The custom of all Yisrael is to cook liver only after roasting it.

Rosh (Chulin 8:27): Rashi connotes that Abaye asked whether one may cook liver after salting it. R. Tam said that surely it is permitted, just like one may cook it after roasting it. Rather, he asked whether one may cook it without salting. Perhaps the Torah permitted it, even though it is all blood. The question was not settled. The Rif does not forbid liver that was cooked without roasting. The Stam Mishnah says that liver forbids, but is not forbidden! Rather, he teaches that the custom is to permit l'Chatchilah only after roasting.

Ran (Chulin 39b DH Garsinan): The Ramban (11a DH v'Asikna) says that if one tore the liver, salted it and cut it (and cooked it), we do not forbid it and what it was cooked with. Since it is a decree of Acharonim, we are not stringent b'Di'eved. The Torah is concerned for the money of Yisrael.

Question (Beis Yosef DH v'Chasav ha'Ramban): Granted, they say that we do not know how to do Chlaitah. However, we know how to tear and salt! Why does the Rif permit only after roasting? I explain that Abaye knew that salting does not help for liver. He asked whether the Torah permitted it, i.e. its blood does not forbid at all, and one may cook it even with meat. Or, perhaps one may cook it only by itself.

Rambam (Hilchos Ma'achalos Asuros 6:7): If one cut liver and cast it in vinegar or boiling water, until it whitened, one may cook it afterwards. The custom of all Yisrael is to roast it and then cook it, whether it is cooked alone or with other things.

Rambam (8): If liver was cooked with other things without roasting or Chalitah, the pot, liver and other food are all forbidden.

Ramban (Chulin 12a DH v'Sham'inan): Our Sugya connotes that we follow the majority even regarding lesions in the lungs. In most animals, nothing is Tereifah at all. Even so, our ancestors always checked for lesions in the lungs, for it is a common Tereifah. We do not rely on the majority l'Chatchilah when the minority is common. We say (Beitzah 25b) that a young tree (we wait three years before eating regarding fruits) rebukes butchers (who do not wait to check the lungs) and people who have Bi'ah with Nidos. We do not discuss people who eat Treifos. They do not check lest they lose the entire animal. Rather, we discuss when it would be permitted afterwards, like Nidah. The Gemara there (25a) said that we learn proper conduct from Olah, not to eat before flaying and dissection. This teaches unlike Rav Huna, who permits a slaughtered animal unless we know that it is Tereifah. The Gemara asked that the Mishnah is like Rav Huna! One may slaughter a dangerously sick animal on Yom Tov if there is time to eat a k'Zayis. Tana'im argue about whether the k'Zayis is roasted or raw. No one requires time to flay, dissect, or look for lesions! This is not difficult. There we give the Torah law. For a dangerously sick animal, we leave the Torah law in place. We do not permit eating without checking. Rather, since the Torah permits eating without checking, this is called Ochel Nefesh (slaughtering at the end of Yom Tov, so that there is time to eat only without checking). A support is that one may slaughter even if he already ate and does not intend to eat more. Normally, one may not cook more. Here Chachamim were lenient, for the Torah is concerned for the money of Yisrael. Normally, mid'Rabanan one may not eat before checking. This is like the opinion that says Ho'il (since guests may come, the Torah permits cooking on Yom Tov even if he does not intend to eat - Beitzah 21a). According to the opinion that disagrees, one may cook only if he intends to eat. We must say that Chachamim permitted eating without checking, since it is impossible to check (and eat during the day). This is like eggs and milk, which we eat (even though we cannot check the Kashrus of the bird or cow while it is alive).

Me'iri (Chulin 49b DH Kol): When a case comes to a Chacham and he can permit easily without (taking one side in an) argument, he should not go beyond the letter of the law to seek excessive stringencies. Rather, he should be concerned for the money of Yisrael, like the Torah is.

Sefer haManhig (Hilchos Devar ha'Avud 523 DH ha'Chayatim): Rav harvested on Chol ha'Mo'ed (Mo'ed Katan 12b). From here we learn that one may prune and plow vineyards when needed during Chol ha'Mo'ed. If the Mo'ed will pass and one will delay doing this, there will be a loss. One may harvest something to avoid a small loss through Yisrael, and all the more so through Nochrim, for the Torah is concerned for the money of Yisrael. Devar ha'Avud is permitted. Likewise, one may plaster barrels, for it is Devar ha'Avud, as long as he did not intentionally leave this for the Mo'ed.

Avi ha'Ezri (Teshuvah 1050): It should not be light in your eyes to waste money of Yisrael. The Torah is concerned for the money of Yisrael. We hold that a Safek mid'Rabanan is permitted. Nowadays we are not concerned for any shaking (of wine) that a Nochri does.

Sefer ha'Machri'a (DH Garsinan): Just like one may not permit what is forbidden, he should not forbid what is permitted. In several places we find that The Torah is concerned for the money of Yisrael. However, one should distance from Isur, and not estimate exactly. The Heter must be clearly more than 60 times the Isur. Do not say that it must be 60 times the volume of the spoon, for the entire spoon is not milk. This is wasting money without reason! Rather, we insert a similar spoon in boiling milk, and see how much it absorbs.

Poskim

Shulchan Aruch (YD 73:1): The liver has much blood. Therefore, l'Chatchilah one may not cook it through salting. B'Di'eved, if it was cooked by itself in a pot (Rema - without roasting), it is permitted. However, the pot is forbidden, for it (the liver) emits (blood) and does not absorb.

Shach (6): B'Di'eved the liver is permitted even if the liver was not salted. Anything cooked with it is forbidden.

Gra (10): It was a mere Dichuy to say that the Mishnah discusses a liver forbidden (for another reason).

Taz (3): It is forbidden l'Chatchilah because one Tana forbids if it was cooked a lot, and we are not proficient (what is considered a lot).

Shulchan Aruch (ibid.): Some forbid (even the liver).

Taz (4): This is like the Rambam, who rules like Chachamim of R. Yochanan ben Nuri. Most rule like R. Yochanan ben Nuri. Our custom is to be stringent, like the Rema says. The Maharshal is lenient, just one must rinse the liver, since the gravy became forbidden. I say that we do not deviate from the custom.

Gra (11): The Rambam (Perush ha'Mishnayos Terumos 10:11) says that R. Yochanan ben Nuri (and the other Tana'im in Mishnah 11) argue with the Stam Mishnah (10). The Halachah follows the Stam Mishnah. He holds that Rav Huna and Rav Nachman required Chalitah even to cook liver by itself. 'Tana'im argue about this', i.e. Abaye's conclusion that liver is not forbidden. Rav Huna and Rav Nachman hold like the first Tana, who forbids (unless Chalitah was done).

Rema: Our custom is to forbid everything even if it was salted before it was cooked.

Shach (8): This is because one Tana forbids if it was cooked a lot, and we are not proficient.

Gra (12): This is correct. We are not stringent due to the Rambam's opinion, which forbids in every case. The other Meforshim hold that Tana'im argue about the law of Rabah and Rav bar Sheva.

Yad Avraham: Toras Chatas (of the Rema, 24:2) permits the pot. Minchas Yakov (3) explains that this is when the liver was salted, and asked why he omitted this in the Shulchan Aruch.