Yevamos 5:6 - 6:1

חלץ ועשה מאמר נתן גט ובעל – it refers to one levir and one widow whose husband died childless (i.e., Yevamah). And even though that this is taught above, [the Mishnah] teaches it again because of the concluding segment that is necessary to separate between an act of coition and Halitzah, for Halitzah, whether at the beginning, whether in the middle or whether at the end – there is nothing after it, and the act of intercourse especially at the time when it is at the beginning, and to teach us also the dispute of Rabbi Nehemiah and the Rabbis.

בין בתחלה בין באמצע – as, for example, [the delivery of] a Jewish bill of divorce to this one and performing Halitzah with that one, and then he went back and made a declaration of intention [to perform a levirate marriage] or with the woman who had the Jewish bill of divorce. The declaration of intention has no effect and we don’t require a Jewish bill of divorce to his declaration of intention [of desiring a levirate marriage].

בסוף – After a declaration of intention [to perform a levirate marriage] and a Jewish bill of divorce, he performed Halitzah, there is nothing after it, for it is a complete Halitzah but if he retracted made a declaration of intention [of levirate marriage] , it doesn’t require a Jewish bill of divorce because Halitzah is a complete Jewish divorce, and even though it is was a disqualified Halitzah.

הביאה באמצע – as in the case of a Jewish bill of divorce to this one and he performed an act of coition to the other woman and then he returned and made a declaration of intention with the third, he prohibited [to marry] her relatives.

בסוף – a Jewish bill of divorce to this one and a declaration of intention [to perform a levirate marriage] to that one, and then he retracted and came [upon her] on [the first, there is after this act of coition the levirate connection and when he releases her, he requires Halitzah and [the reception of] a Jewish bill of divorce is not enough for her.

אין אחריה כלום – and she leaves with a Jewish bill of divorce, without Halitzah, for if he retracted and betrothed to the other one after the act of coition, his deeds are not worth anything.

הבא על יבמתו. שוגג – as he was thinking that she was another woman.

מזיד – for the sake of unchastity and not for the Mitzvah of levirate marriage.

אפילו הוא שוגג והיא מזידה – needless to say where she intended [to fulfill] the Mitzvah but rather even where both of them don’t have the intention [of fulfilling] the Mitzvah such as the case where he intends for another woman, and she had the intention for the sake of unchastity, he has acquired her [as his wife], as it states in Scripture (Deuteronomy 25:5): “ Her husband’s brother shall unite with her: [he shall take her as his wife and perform the levir’s duty],” anyway.

המערה – that he did not complete his coition, but rather, he inserted the corona of his membrum virile alone, and the meeting of the corona without insertion is called “kissing.”

קנה – and he took possession of the inheritance and she is removed with a Jewish bill of divorce if he comes to remove her.

לא חלק בין ביאה לביאה – whether a coition in its proper manner or a coition not in its proper manner, as it is written (Leviticus 20:13): “[If a man lies with a male] as one lies with a woman,” the Biblical verse tells us that there are two ways of sexual gratification.