Yevamot

If his mother, however, was a woman that had been outraged by his father and was then married to his paternal brother who subsequently died, such a mother does exempt her rival.  And though the Sages taught in our Mishnah FIFTEEN we must add a case like this as a sixteenth. Resh Lakish said to R. Johanan: According to Levi who maintains that an 'if'  is also included,  let our Mishnah also include  the case of a levir who gave halizah to his sister-in-law  and later betrothed  her and died without issue, for since [the widow of such a one] is forbidden,  her rival also is forbidden!  — The other replied: Because in this case the law of the rival of the rival  cannot be applied.  But could he  not have answered  him  [that the brothers] are only subject to the penalties of a negative precept,  and that those who are subject to the penalties of a negative precept are  under the obligations of halizah and the levirate marriage?  — He  answered him  in accordance with the view he  holds. 'According to my view,' he  argued, [the brothers] are only subject to the penalties of a negative precept,  and those who are subject to the penalties of a negative precept are  under the obligations of halizah and the levirate marriage,  but even according to your view that they are subject to the penalty of kareth [the case could not have been included in our Mishnah] because the law of the rival's rival cannot be applied'. It has been stated: Where [a levir] had performed the ceremonial of halizah with his sister-in-law, and then betrothed her, Resh Lakish holds that he is not subject to the penalty of kareth for the haluzah,  but the other brothers are subject to kareth for the haluzah.  In the case of the rival,  both he  and the other brothers are subject to kareth for a rival.  R. Johanan, however, holds that neither he  nor the other brothers are subject to kareth either for the haluzah or for her rival.  What is the reason of Resh Lakish? — Scripture stated, That doth not build,  since he has not built he must never again build.  He himself is thus placed under the prohibition of building no more,  but his brothers remain in the same position in which they were before.  Furthermore, the prohibition to build no more applies only to herself,  her rival, however, remains under the same prohibition as before.  And R. Johanan?  — Is it inconceivable  that at first halizah should be allowed to be performed by any one of the brothers  and with either of the widows of the deceased brother  and that now one or other of these persons should  be involved in kareth!  But [in point of fact] he  merely acts as agent for the brothers while she  acts as agent for her rival. R. Johanan pointed out to Resh Lakish the following objection: 'If a levir who submitted to halizah from his sister-in-law, later betrothed her and died,  [the widow] requires halizah from the surviving brothers'. Now, according to me who maintains that [the surviving brothers]  are subject to the penalties of a negative precept only, one can well understand why she requires halizah from the other brothers.  According to you, however, why should she require halizah?  — Explain, then, on the lines of your reasoning, the final clause, 'If one of the brothers  actually  betrothed her, she has no claim upon him'!  R. Shesheth replied: The final clause represents the opinion of R. Akiba who holds that a betrothal with those who are subject thereby to the penalties of a negative precept is of no validity.  Should it not then have been stated, 'according to the view of R. Akiba she  has no claim upon him'!