Eruvin 82A

גברא אגברא קא רמית?! מר סבר פליגי, ומר סבר לא פליגי.

Are you raising a contradiction between the opinion of one person and that of another? In other words, a difficulty cannot be raised from the statement of one amora against those of another. One Sage, Shmuel, maintains that R' Yehuda and the rabbis disagree, and one other Sage, R' Yehoshua ben Levi, maintains that they do not disagree.

גופא, אמר רבי יהושע בן לוי: כל מקום שאמר רבי יהודה ״אימתי״ ו״במה״ במשנתינו ⁠— אינו אלא לפרש דברי חכמים. ורבי יוחנן אמר: ״אימתי״ לפרש, ו״במה״ לחלוק.

The Talmud analyzes the statement of R' Yehoshua ben Levi cited in the course of the previous discussion. With regard to the matter itself: R' Yehoshua ben Levi said that any place where R' Yehuda says when, or in what case are these, in the Mishnah, he intends only to explain the earlier statement of the Rabbis, not to disagree with them. And R' Yoḥanan said: The term when indicates that R' Yehuda comes to explain, but the phrase in what case is this, indicates that he intends to disagree.

ו״אימתי״ לפרש הוא? והא תנן: ואלו הן הפסולים: המשחק בקוביא, ומלוה בריבית, ומפריחי יונים, וסוחרי שביעית.

The Talmud raises a difficulty: Is the word when invariably a sign that R' Yehuda merely seeks to explain? Didn’t we learn in a Mishnah: The following people are disqualified by the rabbis from giving testimony, as they are people who commit transgressions for profit: One who plays with dice [kubiyya] for money, and one who lends money at interest, and those who fly pigeons, i.e., people who arrange competitions between pigeons while placing wagers on which bird will fly faster. The reason for their disqualification is that those who play games of chance do not fully relinquish ownership of their gambling money, as they expect to win their bet. Consequently, one who accepts money in such circumstances has effectively taken something that the giver has not wholeheartedly handed over, and he is therefore like a robber, at least by rabbinic decree. The list of those disqualified from giving testimony includes merchants who trade in the produce of the Sabbatical Year, which may be eaten but may not be sold as an object of commerce.