1. איסור to cook a גדי in its older sister’s milk, and a mother in her own milk

A Baraisa darshens a superfluous "בחלב אמו" to prohibit cooking a גדי’s meat in the milk of cows and ewes, rather than only its mother’s milk. This cannot be derived from a kal vachomer (based on their prohibition to be mated with a goat, in contrast to its mother), because its mother has its own stringency, in being forbidden to be shechted on the same day as her kid. The Gemara proceeds to derive from a צד השוה that it is also forbidden to cook a גדי’s meat בחלב אחותו גדולה – in the milk of its older sister (i.e., born in a different year), שלא נכנסה עמו לדיר להתעשר – which cannot enter the pen with it to be tithed. Although it cannot be derived from the mother alone, because of the stringency of אותו ואת בנו, nor from cows and ewes alone, which are prohibited to be mated with a גדי, together they teach that no milk and meat can be cooked together. Another superfluous "בחלב אמו" is eventually darshened to prohibit היא עצמה בחלבה – cooking [the mother’s] own meat in her milk. Rav Ashi ultimately explains that it cannot be derived from cooking a גדי in its mother’s milk, שכן שני גופים – which are two separate bodies, in contrast to cooking the mother in her own milk, שכן גוף אחד – which are of one body.

1. Rebbe Abahu’s Principle for deriving any benefit from בשר בחלב (כל מקום שנאמר לא יאכל...)

Rav Ashi provides a source for the prohibition against eating בשר בחלב. The passuk says: לא תאכל כל תועבה – you shall not eat any abomination, meaning: כל שתעבתי לך הרי הוא בבל תאכל – anything I have made abominable for you by forbidding it is included in the prohibition, “you shall not eat.” The prohibition against deriving any benefit from it is derived from Rebbe Abahu’s principle: כל מקום שנאמר לא יאכל לא תאכל לא תאכלו – wherever it says in the Torah “one shall not eat,” “you (singular) shall not eat,” or “you (plural) shall not eat,” אחד איסור אכילה ואחד איסור הנאה במשמע – both a prohibition against eating and a prohibition against benefit are implied, עד שיפרוט לך הכתוב כדרך שפרט לך בנבלה – unless the passuk specifies that benefit is permitted, as it specified for you regarding neveilah, permitting gifting or selling it to a non-Jew (thus permitting benefit from נבלה). This implies that unless specified, a prohibition against “eating” also prohibits any benefit.

1. Machlokes if נבלה can only be gifted to a גר or sold to an idolator, or can be gifted and sold to both

A passuk says regarding a neveilah: לגר אשר בשעריך תתננה ואכלה או מכור לנכרי – to the [non-Jewish] resident alien who is within your gates you shall give it that he may eat it, or sell it to a gentile. Rebbe Meir says it may also be sold to a גר, because the passuk can be read: לגר...תתננה...או מכור – to a גר you shall give it or sell it. It may also be gifted to an idolator, because the passuk can be read: תתננה...או מכור לנכרי – you shall give it or sell it to a gentile. Rebbe Yehudah disagrees and says: דברים ככתבן – the words should be understood as they are written, that it may only be gifted to a גר, or sold to an idolator. If Rebbe Meir were correct, the Torah should have written “you shall give it and sell it…”; the word "או" – or indicates that each option is specific to that respective person. Rebbe Meir replies that "או" teaches להקדים נתינה דגר למכירה דעובד כוכבים –to give precedence to gifting to a גר over selling to an idolator. Rebbe Yehudah says this is self-evident, since regarding the ger, אתה מצווה להחיותו – you are obligated to sustain him, unlike an idolator.

Siman – Kiddie Park. The new בחלב אמו kiddie park that had various types of milk hoses to demonstrate that all milk is assur with meat such as the milk of the gedi’s older sister, had a roped off בשר בחלב snacking section because if you can’t eat there you can’t even benefit from sitting there, and a vendor giftingנבלה to geirim and selling it to נכרים.