Yevamot

if he  participated in the halizah with the sisters, the rivals are not exempt;  how then should Reuben,  where the halizah of Simeon  has the force of a valid halizah,  participate in an impaired halizah?  — By saying. 'One brother participates in the halizah with all of them' he also meant 'the third widow'.  But surely, 'All of them' was stated!  -As the majority is on his side  it may be described as 'All of them'. If you prefer I might say: Only in respect of exempting one's rival  did Samuel say that proper halizah was required; as regards exempting herself, however, [any halizah]  sets her free. [To turn to] the main text,  Samuel said: If he  participated in the halizah with the sisters, the rivals are not exempt;  ff with the rivals. the sisters are exempt.  If he  participated in the halizah with the one  who had been divorced,  her rival is not thereby exempt;  if with the rival  the divorced woman is exempt — 22 If he  participated in the halizah with one  to whom he addressed a ma'amar, her rival is not thereby exempt;  if with the rival,  the widow to whom the ma'amar had been addressed is exempt. In what respect are the sisters different that [by their halizah] the rivals should not be exempted? Apparently because [each one of them] is 'his wife's sister' through the levirate bond;  [but for this very reason] the sisters also, if he participated in the halizah with their rivals, should not be exempt, since those are the rivals of 'his wife's sister' through the levirate bond!  — Samuel holds the opinion that no Ievirate bond exists. But, surely, Samuel said that a levirate bond did exist!  -He was here speaking in accordance with the view of him who maintains that a levirate bond does not exist. If so,  why are not the rivals exempt when he participated In the halizah with the sisters? One can well understand why Rachel's  rival is not exempt; for, as he had already participated in the halizah of Leah  and only subsequently participated in the halizah of Rachel, Rachel's halizah is a defective one;  but Leah's rival should be exempt!  -When he  said that 'The rivals are not exempt', he meant indeed the rival of Rachel. But, surely, he used the expression 'rivals'!  -Rivals generally. If so,  how could the sisters be exempt if he participated in the halizah with their rivals? Is Rachel exempt by the halizah of her rival!  Surely we learned: A man is forbidden to marry the rival of the relative of his halizah  — Samuel also [is of the same opinion] but draws a distinction according to the manner In which  one began or did not begin: If one began with the sisters  he must not finish with the rivals,  for we learned, 'A man is forbidden to marry the rival of the relative of his haluzah';  but if he began with the rivals  he may finish even with the sisters,  for we learned, 'A man is permitted to marry the relative of the rival of his haluzah'. R. Ashi said: Your former assumption  may still be upheld, and [yet no difficulty  arises] because the levirate bond is not strong enough to make the rival equal to the forbidden relative herself. It was taught in agreement with the view of R. Ashi: If the levir participated in the halizah with the sisters, their rivals are not thereby exempt; but if with the rivals, the sisters are thereby exempt. What is the reason? Obviously  because he is of the opinion that a levirate bond exists and that that bond is not strong enough to make the rival equal to the forbidden relative herself. R. Abba b. Memel said: Who is the author of this?  Beth Shammai; for we learned: Beth Shammai permit the rivals to the [surviving] brothers.  If so,  let them  be taken in levirate marriage also!  [This is] in agreement with R. Johanan b. Nuri who said: Come, let us issue an ordinance that the rivals perform the halizah but do not marry the levir.  But did not a Master say that they had hardly time to conclude the matter before confusion set in?  — R. Nahman b. Isaac replied: After him  they re-ordained it. The question was raised: