Berachos 3:6 - 4:1

זב שראה קרי – Even though that he [who is afflicted with gonorrhea] has made himself impure for seven days because of his gonorrhea, and his immersion [in the Mikveh/ritual bath] does not purify him, nevertheless, he requires immersion according to the words of the Torah, according to the enactment of Ezra , since one who has a nocturnal emission and a menstruant woman , if she came to pray and discharged her seed, she considered to be like one who had a nocturnal emission, as a woman who releases her seed is defiled through her emission for three days after sexual intercourse. And from then onwards, her seed has decayed in her body and its not appropriate of having a fetus created from it. And this is the explanation concerning a menstruant woman who emits her seed during the time of intercourse which she engaged in the previous night before she saw it and when she engages in sex and finds that she is a menstruant woman; after she had engaged in intercourse, she requires ritual immersion.

ורבי יהודה פוטר – Even a woman who engaged in sexual intercourse and saw that she had become a menstruant woman, Rabbi Yehuda exempts, even though ab initio, she should immerse herself, and one can say that her obligation of immersion was prevented. And we have already written above that she did not have to engage in ritual immersion because it was a decree that most of the community could not could not follow.

תפלת השחר עד חצות – Since the morning daily offering is offered until noon, according to the Rabbis, and according to Rabbi Yehuda, is not offered other than up until the fourth hour of the day. “Until the fourth hour” is until the end of the fourth hour which is one-third of the day at the time when the day has twelve [equivalent] hours, and so is its time is forever, until the end of the first third of the day, according to the length or shortness of their daytimes, as we have written above regarding the [recitation of the] Shema. And the Halakha follows Rabbi Yehuda.

תפלת המנחה עד הערב – until it gets dark.

עד פלג המנחה – the time of the “small Minha” which is from nine-and one-half hours [into the day] until the nighttime, which is [the equivalent of] two-and-one-half hours. Hence it is found that “Plag HaMinha” is one half of this measure which is one and one-quarter hours, and that the determined law/practice [in this matter] is that he who followed [the Sages] followed them, and he who followed [Rabbi Yehuda] followed him, and he who wants to follow the words of the Sages and recite the afternoon prayer until the evening should do so, as long as he does not recite the evening prayer at that time, since he considers that daytime period for the matter of reciting the afternoon service, he is not able to consider it nighttime and to recite] the evening service. But, if he comes to act according to the words of Rabbi Yehuda, that he should not recite the afternoon service other than until “Plag HaMinha” (i.e., 4:45 pm), which is an [halakhic] hour-and-a-quarter before the nighttime, he should do so, and from that point onwards, he may recite the evening service.

אין לה קבע – Its time [the evening service] is all night long, but when it [the Mishnah] teaches, “Ein Lah K’vah/It has no fixed time,” and it doesn’t teach, “its time is all night long” – it comes to teach us that the evening service is optional, since it was [considered] parallel to the offering of the limbs and fats which are offered all night, and these are optional, since when the blood is poured, the sacrifice is accepted, even though the limbs and fats were defiled or lost. However, nowadays, it (the recitation of the evening service), has been accepted as obligatory.

ושל מוספין כל היום – But if he recited [Musaf] later after the seventh hour, he has fulfilled his religious obligation, but he is called a sinner, and this is the Halakha.