WHICH MEAT IS FORBIDDEN WITH MILK?
(continuation of Mishnah): One who vows not to eat meat is permitted to eat meat of fish and grasshoppers.
(Gemara) Question: Our Mishnah holds that the Torah forbids cooking fowl with milk. Who is the Tana?
Answer: It is not R. Akiva, for he holds that the Isur of Chayos or birds with milk is only mid'Rabanan.
Question (Seifa): One who vows not to eat meat is permitted meat of fish and grasshoppers.
This implies that he is forbidden to eat fowl. This is like R. Akiva, who says that anything a messenger would ask about is considered the same species!
(Mishnah): If one vowed not to eat Yerek (this word connotes certain species of vegetables), he may eat pumpkin;
R. Akiva forbids.
Chachamim: If a messenger was sent to get Yerek (and didn't find any), he would say 'I found only pumpkin.' (This shows that pumpkin is not considered Yerek!)
R. Akiva: To the contrary! He would not respond 'I only found Kitnis (legumes, e.g. peas, because Kitnis is not considered Yerek at all, but pumpkin is)'!
Summation of question: Is the Reisha Chachamim, and the Seifa R. Akiva?!
Answer #1 (Rav Yosef): The Mishnah is like Rebbi. He holds like R. Akiva regarding vows, and like Chachamim regarding meat and milk.
Answer #2 (Rav Ashi): The whole Mishnah is like R. Akiva;
The Reisha means that one may not cook any kind of meat with milk. Some kinds are forbidden mid'Oraisa, and others, mid'Rabanan;
Only meat of fish and grasshoppers is permitted even mid'Rabanan.
A DECREE TO GUARD A DECREE
(Mishnah): One may not bring cheese...
Inference (Rav Yosef): This shows that the Torah forbids (eating) fowl (cooked with) milk. If it were only a Rabbinic decree, we would not forbid putting them on the same table. That would be a decree to guard a decree!
Question: What is the source that we do not enact a decree to guard a decree?
Answer (Rav Yosef - Mishnah): A Zar (non-Kohen) may eat at the same table with a Kohen eating Chalah of Chutz la'Aretz (which is only mid'Rabanan). Such Chalah may be given to any Kohen (even an ignoramus);
Question (Abaye): That would be a proof if the Mishnah discussed Chalah of Chutz la'Aretz in Eretz Yisrael, where there is reason to decree, lest a Zar or a Tamei ignoramus Kohen eat mid'Oraisa Chalah (of Eretz Yisrael)l
The only reason not to decree would be that we do not make a decree to guard a decree.
In Chutz la'Aretz, there is no concern for any Torah Isur (regarding Chalah). There is no need to decree!
Regarding meat and milk, if we allow fowl and milk on the same table, one may come to put beef and milk on the same table, and eat them together!
Question (Rav Sheshes): Even if the Torah forbids fowl cooked with milk, not putting them on the same table is a decree to guard a decree. The Torah permits eating them together if they are not cooked together!
Answer (Abaye): We decree lest they be put together in a hot pan.
Question: Even so, a Kli Sheni (it was not on the fire, but food from a pot on the fire was poured into it) cannot cook (the meat and milk together)!
Answer: We decree lest they be put in a Kli Rishon (it was on the fire. Such pans can cook.)
THE ARGUMENT ABOUT FOWL
(Mishnah - Beis Shamai): Fowl may be put on the same table as cheese, but they may not be eaten together;
Beis Hillel say, they may not be put on the same table nor eaten together.
R. Yosi says, this is a law in which Beis Shamai are lenient and Beis Hillel are stringent.
They discuss the table on which one eats, but all permit putting them side by side on a table on which one arranges the courses.
(Gemara) Question: Also the first Tana says that Beis Shamai are more lenient (just like R. Yosi)!
Suggestion: They argue about eating. The first Tana says that all forbid eating them together, and R. Yosi says that Beis Shamai permit eating them together.
Rejection (Beraisa - R. Yosi): In six laws, Beis Shamai are lenient and Beis Hillel are stringent. One is that Beis Shamai permit putting fowl and cheese on the same table, but they may not be eaten together;
Beis Hillel say, they may not be put on the same table nor eaten together.
Answer: Indeed, the Mishnah teaches that the first Tana is R. Yosi!
"Esther told the king in Mordechai's name" - whoever says something in the name of its originator brings redemption to the world.
THE REQUIRED SEPARATION BETWEEN MEAT AND MILK
(Agra, the father-in-law of R. Aba - Beraisa): Fowl and cheese may be eaten wantonly.
(Agra): This means that one need not wash his hands or clean his mouth in between.
Rav Yitzchak brei d'Rav Mesharshiya visited Rav Ashi. He ate cheese and then beef without washing his hands in between.
Onlookers: Agra's Beraisa permits eating fowl and cheese wantonly. This implies that beef and cheese are forbidden (without washing)!
Rav Yitzchak: That applies at night. During the day, one can see that his hands are clean.
(Beraisa - Beis Shamai): One cleans his mouth (between meat and milk);
Beis Hillel say, he washes (Rosh - his mouth; Rambam - his hands).