Yibum Laws

The Tractate Yevamot deals primarily with levirate marriages. This is the unusual Mitzva that one is expected to marry his brother’s wife, if he dies childless.

The unique aspect of this Mitzva is that one is forbidden to “uncover the nakedness” of his sister in-law. But all of this changes in the “Yibum” situation, where there is a commandment to marry her.

These rules are waived if the brother’s wife is related in a different way to her brother in-law. The Talmud gives an example of a man who marries his niece, and then dies childless. His brother is also the father of his niece/wife. Since a father cannot marry his daughter, the rules of Yibum are waived, and the new widow is free to marry anyone she wants.

Another interesting case involves two brothers who marry two sisters. If one of the brothers dies, the Yibum rules are also waived. This is because there is another prohibition forbidding marrying two sisters. To complicate matters, one is allowed to marry his wife’s sister, if his wife passes away.

These laws are very interesting and complicated. It is easy to understand why Masechet Yevamot is considered one of the most difficult tractates in the entire Talmud.