Early on in our study of Massechet Yevamot (see for example my commentary to Yevamot 8b) we explained that though the Torah only demands cohabitation in order to transform the partial ‘marriage’ (that is automatically established between a woman whose husband died without children and her brother-in-law upon the death of her husband) into a fully-fledged marriage, it was decided that in order to prevent abuse, and so as to ensure that the practice of yibum is more aligned with classic Jewish marriage, that an intentional marriage-like ceremony called ‘ma’amar’ is required even for yibum and that only after such a ceremony has been performed may the Yavam and Yevama come together in sexual union.
The question, addressed in today’s daf (Yevamot 51a), is what is the legal status of ma’amar? True, ma’amar was rabbinically established as a prerequisite for the concretization of a yibum relationship. But does ma’amar ‘create’ marriage? Or does it merely ‘indicate’ that a marriage is about to occur through cohabitation?
While this topic is hotly debated in our daf, the halacha, as codified in the Shulchan Aruch (Even HaEzer 166:2), is that while ma’amar is certainly required, the need to perform ma’amar does not change the fact that cohabitation is the sole ‘creator’ of the marriage between the Yavam and Yevama.
What we learn from here is that while extra safeguards must be introduced and enforced in some areas of Jewish law to prevent various forms of abuse, these generally do not change the ‘mechanics’ of those areas of Jewish law. Still, what they do achieve is to help us change the ‘dynamics’ of our relationship with those laws.