Yevamot 30: Repetition, Timing and Uncertainties

Amud (a) is composed of three short, related Mishnayot.  Each of them describes cases where three brothers marry two sisters and one unrelated woman.  We watch the rabbis understand the substance of the levirate bond.  What if one of the sisters dies first?  What if the husband of the unrelated woman dies first?  The rabbis play out the principles of levirate marriage through these situations.  We are reminded that rival wives are excluded when their first wives are excluded; sisters are forbidden to the same husband; once forbidden, always forbidden.  The rabbis argue the applicability of these principles to these given cases.  

They also pay attention to possible reasons for including very similar Mishnayot.  One reason suggests that the Mishnayot were placed and now taught in order, so we must keep them that way.  Another reason is that the rabbis want to ensure that Beit Shammai's opinions are shown as erroneous.

Amud (b) continues this conversation.  One of the salient points teaches that the critical moment determining the status of the yevama is that same moment that she becomes a yevama - when her husband dies.  That status - and not what happens later in time - tells us whether or not she will be excluded from the obligation of yibum, levirate marriage.

A new Mishna complicates things further.  We are told that when one of the fifteen women excluded from yibum due to forbidden relationships is betrothed or divorced with uncertainty, any rival wives are also excluded from yibum in all cases.  What is uncertainty?  In betrothal, an uncertainty arises when the object thrown from husband to wife lands somewhere between them or is lost.  In divorce, an uncertainty might be when the get, divorce certificate, is written in the husband's handwriting but with no signatory witnesses.  

Of course, the rabbis discuss these uncertainties and other potential competing uncertainties.  They note that this principle is a stringency, and they argue whether or not we should impose stringent rulings in such cases.  

Levirate marriage only happens in times when men are permitted to be married to more than one woman (not all cases of yibum involve multiple wives, but many do).  My understanding is that this is not practiced and has not been practiced for at least 1500 years.  And yet we learn the tiny details regarding exceptions to this mitzvah.  It is a wonder that more Jews are not lawyers!