- Challah nowadays is only a d’Rabbanon
Rav Huna brei d’Rav Yehoshua said: I found the Rabbanon in the Beis Midrash saying that even according to the one who says that nowadays terumah is only d’Rabbanon, (for he holds that Ezra only sanctified the land until the churban) challah is d’Oraysa, for in the days of Yehoshua, during the seven years of conquest and the seven years they apportioned the land to the shevatim, נתחייבו בחלה ולא נתחייבו בתרומה – they were obligated in the mitzvah of challah but not in the mitzvah of terumah. But I said to them that it is the opposite. Even according to the one who holds that terumah is d’Oraysa (for he holds that Ezra sanctified the land forever), challah is only a d’Rabbanon. For it was taught in a Baraisa: You must separate challah "בבאכם אל הארץ" – upon your coming into the land. Since it states, “upon your coming,” I might have thought the chiyuv begins when two or three meraglim enter the land. Therefore, the Torah states, "בבאכם" – upon “your” coming, which teaches בביאת כולכם אמרתי ולא בביאת מקצתם – upon the coming all of you, I said you must separate challah, and not upon the coming of some of you. And when Ezra came up from Bavel, not all the Jews came up. As a result, challah nowadays is only a d’Rabbanon.
- עדות הבאה מכח חזקה כחזקה
It was taught in a Baraisa: חזקה לכהונה נשיאות כפים וחילוק גרנות ועדות – A chazakah that a man is a Kohen can be established by testifying that he recited birkas Kohanim, or that he received terumah during the distribution at the granaries, and by testimony, which Rashi explains means that witnesses testified that his father was a Kohen and his mother was fit to marry a Kohen. When the Gemara questions how it can say that testimony only establishes a chazakah, when testimony is absolute proof of Kehunah, it concludes that the Baraisa means: עדות הבאה מכח חזקה כחזקה – testimony based on a presumptive status, is like that of presumptive status itself. This is like the case when a man came before Rebbe Ami and said: מוחזקני בזה שהוא כהן – “I presume that this man is a Kohen.” When Rebbe Ami asked him why he thought that, the man responded that he saw him get the first aliyah. When Rebbe Ami suggested that perhaps it was just as a kavod for being a great man, the man replied that he saw a Levi come after him and read second. Rebbe Ami elevated the man to the kehunah, to permit him to eat terumah.
- Elevating a son on the word of his father, and elevating a brother on the word of his brother
Rebbe and Rebbe Chiya gave rulings in different cases: One elevated a son to the kehunah, based on the word of his father, and one elevated a brother to the status of a Levi, based on the word of his brother. The Gemara determines that Rebbe was the one who elevated a son based on the word of his father, from a Baraisa where Rebbe taught: הרי שבא ואמר בני זה וכהן הוא – If someone came and said: “This is my son and he is a kohen,” he is believed to the extent of letting him eat terumah but not to the extent of marrying a woman of yichus. He explained to Rebbe Chiya, who disagreed, that he believes him regarding terumah שבידו להאכילו בתרומה – since it is in the father’s power to give him terumah to eat. Rashi explains that the father is a kohen and people give him terumah, but it is not in the father’s power to marry him off to a woman of yichus. The Gemara asks why Rebbe Chiya rejected the testimony of the father about the son but accepted the testimony of the brother about the brother, even though he is also a relative, and answers, במסיח לפי תומו – the case was where the brother was speaking casually, without awareness and intent to help his brother.