Ketubot 2A

בתולה נשאת ליום הרביעי ואלמנה ליום החמישי. שפעמים בשבת בתי דינין יושבין בעיירות: ביום השני וביום החמישי, שאם היה לו טענת בתולים, היה משכים לבית דין.

Mishnah: A virgin is married on Wednesday and a widow on Thursday. The reason for the former is that twice a week courts convene in the towns, on Monday and Thursday, so that if the husband had a claim concerning the bride’s virginity when consummating the marriage on Wednesday night, he would go early the next day to court and make his claim.

גמ׳ אמר רב יוסף אמר רב יהודה אמר שמואל: מפני מה אמרו בתולה נשאת ליום הרביעי? לפי ששנינו: הגיע זמן ולא נישאו ⁠— אוכלות משלו, ואוכלות בתרומה.

Talmud: Rav Yosef said that Rav Yehuda said that Shmuel said: Due to what reason did they say that a virgin is married on Wednesday? It is because we learned in a Mishnah elsewhere (57a): If the time that the groom designated for the wedding arrived, and the wedding was postponed, and they were not married, the brides are entitled to eat from his food and, if he is a priest, eat teruma.

יכול הגיע זמן באחד בשבת יהא מעלה לה מזונות? לכך שנינו: בתולה נשאת ליום הרביעי.

One might think that if the designated time arrived on Sunday, and the wedding was postponed, he would provide her sustenance beginning on Sunday. Therefore, we learned: A virgin is married on Wednesday. Until Wednesday, the designated time is not considered to have arrived, even if the original date was earlier in the week.

אמר רב יוסף: מריה דאברהם! תלי תניא בדלא תניא?! הי תניא והי לא תניא? הא תניא והא תניא! אלא: תלי תניא דמפרש טעמא בדתניא דלא מפרש טעמא.

After citing the statements above, Rav Yosef said in astonishment: Lord of Abraham, Shmuel makes that which is taught dependent on that which is not taught, using the latter to explain the former. The Talmud asks: Which is taught and which is not taught? Both this Mishnah is taught and that Mishnah is taught. The Talmud answers: Rather, Shmuel makes the halakha that is taught in the Mishnah here, whose reason is explicit, dependent on a halakha that is taught in the later Mishnah, whose reason is not explicit. Citation of the later Mishnah contributed nothing to the understanding of the Mishnah here.