Study Shabbat folio 121A with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
טבילה בזמנה לאו מצוה ומהדרינן, ורבי יוסי סבר טבילה בזמנה מצוה ולא מהדרינן.
that performing immersion at its designated time is not a mitzva, and we seek a reed to wrap around God’s name even if it means postponing immersion to the next day, and R' Yosei holds that immersion at its designated time is a mitzva, and therefore we do not seek a reed, since immersion cannot be postponed.
וסבר רבי יוסי טבילה בזמנה מצוה? והתניא: הזב והזבה, המצורע והמצורעת, בועל נדה וטמא מת, טבילתן ביום. נדה ויולדת — טבילתן בלילה. בעל קרי — טובל והולך כל היום כולו. רבי יוסי אומר: מן המנחה ולמעלה אינו צריך לטבול! ההיא, רבי יוסי ברבי יהודה היא, דאמר: דייה טבילה באחרונה.
The Talmud asks: And does R' Yosei hold that immersion at its designated time is a mitzva? Wasn’t it taught in a baraita: With regard to a zav and a zava, a male and female metzora, one who has sex with a menstruating woman, and a person impure with impurity imparted by a corpse, their immersion is during the day. They immerse at the designated time even on Yom Kippur, when bathing is prohibited. A menstruating woman and a woman after childbirth immerse at night. A man who has had a seminal emission immerses at any point during the entire day after the emission. R' Yosei says: From the time that he recited the afternoon prayer and on he does not immerse. Since he already recited the afternoon prayer, he waits until after Yom Kippur to immerse, and then recites the evening prayer in a state of purity. Apparently, R' Yosei holds that immersion at the designated time is not a mitzva. The Talmud rejects this: In that baraita the reference is not to the R' Yosei most commonly cited in tannaitic literature without a patronymic, R' Yosei ben Ḥalafta, but it is to R' Yosei, son of R' Yehuda, who said: Her latest immersion is sufficient. A woman who is uncertain with regard to the correct time for her immersion need not immerse multiple times. She may postpone her immersion until a time when she will be certain to fulfill her obligation, even though it might not be immersion at the designated time.
Text data via Sefaria: William Davidson Edition - English and William Davidson Edition - Vocalized Aramaic, CC-BY-NC; edition provenance: Koren. Display terminology has been modernized for readability.