Yevamot

— This is rather a difficulty. R. Ashi holds the same opinion as Resh Lakish  and explains it  in accordance with the ruling of R. Simeon.  Rabina holds the same opinion as R. Johanan  and explains it  in accordance with the ruling of the Rabbis.  'R. Ashi holds the same opinion as Resh Lakish and explains it in accordance with the ruling of R. Simeon', thus: If [a levir] who submitted to halizah from his sister-in-law had subsequently betrothed her, she  requires halizah from the brothers. Who are these brothers? Those born [subsequently].  According to whose view? According to that of R. Simeon.  If one of the previously born  brothers, however, betrothed her, she has no claim upon him.  According to whose view? According to that of Resh Lakish. 'Rabina holds the same opinion as R. Johanan and explains it in accordance with the ruling of the Rabbis', thus: If [a levir] who submitted to halizah from his sister-in-law had subsequently betrothed her, she requires halizah from the brothers. Who are these brothers? Those born [prior to the halizah]. According to whom? According to R. Johanan.  If one of the subsequently  born brothers, however, betrothed her, she has no claim upon him. According to whose view? According to that of the Rabbis. It has been stated: In the case where [the Ievir] had intercourse with his sister-in-law  and one of the other brothers had intercourse with her rival, there is a difference of opinion between R. Aha and Rabina. One said: [It involves  a transgression subject] to kareth and the other said: [The transgression] of a positive precept.  He who said, '[A transgression subject] to kareth' follows Resh Lakish;  and he who said, '[The transgression] of a positive precept' follows R. Johanan. Rab Judah said in the name of Rab: The rival of a sotah  is for bidden.  What is the reason?  — Because uncleanness is ascribed to her  as to the cases of incest.  R. Hisda raised an objection:  R. Simeon  said, the intercourse  or halizah of the brother of the first husband exempts her rival!  — Rab can answer you, 'I speak of a sotah that is Biblically forbidden,  and you talk of a sotah that is only Rabbinically forbidden'. But as to him who raised this objection, what did he imagine?  — He thought that Rabbinical provisions were given the same force as Biblical laws. R. Ashi raised an objection: If she  entered with the man into a private place and remained with him for a period sufficient for the consummation of defilement, she is forbidden to her house,  she may not eat of terumah,  and if he died she must undergo the ceremony of halizah