מה מצחיק פה?

גמרא בבא קמא י"ז

מַתְנִיתִין: כֵּיצַד הָרֶגֶל מוּעֶדֶת לִשְׁבֹּר בְּדֶרֶךְ הִלּוּכָהּ הַבְּהֵמָה מוּעֶדֶת לְהַלֵּךְ כְּדַרְכָּהּ וּלְשַׁבֵּר.

MISHNA: The mishna in the previous chapter (15b) teaches that the owner of an animal is always forewarned with regard to the category of Trampling. The mishna elaborates: For what damage caused with the hoof is the animal deemed forewarned? It is deemed forewarned with regard to trampling objects and breaking them in the course of its walking. An animal is deemed forewarned with regard to walking in its typical manner and, by doing so, breaking objects as it proceeds.

א"ל רָבִינָא לְרָבָא הַיְינוּ רֶגֶל הַיְינוּ בְּהֵמָה א"ל תְּנָא אָבוֹת וְקָתָנֵי תּוֹלָדוֹת.

GEMARA: The Gemara analyzes the mishna: Ravina said to Rava: In the context of the category of Trampling, damage caused by an animal trampling an object with its foot is the same as damage caused by an animal breaking an object with its body. Why does the mishna repeat the same halakha twice? Rava said to him: First, the tanna teaches the primary categories of damage, namely the category of Trampling with an animal’s foot, which is mentioned explicitly in the Torah, and then he teaches the subcategories of those primary categories, i.e., the animal is deemed forewarned with regard to causing damage with other parts of its body in the course of its walking.

אֶלָּא מֵעַתָּה סֵיפָא דְּקָתָנֵי הַשֵּׁן מוּעֶדֶת הַבְּהֵמָה מוּעֶדֶת מַאי אָבוֹת וּמַאי תּוֹלָדוֹת אִיכָּא הֲוָה קָמַהְדַּר לֵיהּ בִּבְדִיחוּתָא וא"ל אֲנָא שַׁנַּאי חֲדָא וְאַתְּ שַׁנִּי חֲדָא.

Ravina challenges this explanation: If that is so, the latter clause of the mishna (19b), which teaches, concerning the primary category of Eating: For what damage caused by Eating is the animal deemed forewarned? It is deemed forewarned with regard to eating food items fit for its consumption, i.e., the animal is deemed forewarned with regard to eating fruits and vegetables. Ravina asks: What primary categories and what subcategories are there in that context? No subcategories of Eating are enumerated there, and nevertheless, the phrase: The animal is deemed forewarned, is repeated. Rava responded to Ravina with a humorous response and said to him: I resolved the difficulty in one mishna, now you resolve the difficulty in one mishna.

וכי מילתא דבדיחותא היא זו כאשר הרב מדרבן את תלמידיו שימשיכו בדרכו לחדש תירוצים בישוב המשנה?

אלא שבדיחותא היא פתיחותא שכן אות ב' מתחלפת באות פ' ואות ד' מתחלפת באות ת', וכמבואר בקישור זה. ומילתא דבדיחותא היא בפתיחת השיעור, כאמור במסכתות שבת דף ל ע"ב; ופסחים דף קיז ע"א: "דרבה, מקמי דפתח להו לרבנן אמר מילתא דבדיחותא, ובדחי רבנן. לסוף יתיב באימתא ופתח בשמעתא". וכך אמר רבא לתלמידיו: אני פתחתי ואתם תסיימו.

הרב כוכב