noam kranz asked:
in tos. d.h. kidsa b'kaspa tos says chazal can't uproot a kiddushin of biah because of an aveira. what is that avaira.
noam kranz, passaic, N.J.
The Kollel replies:
He is referring to a Bi'as Zenus (see Rambam, Hilchos Ishus 1:1,4), i.e. extramarital relations.
It is true that once the Rabanan uproot Kidushei Kesef, this will also cause all of the subsequent Bi'os into Bi'os Zenus. However, that is only a "Grama"; the Rabanan aren't making the act into an act of Zenus directly , only indirectly. On the other hand, when the Rabanan uproot Kidushei Bi'ah, they are making the Bi'ah of the Kidushin (which effected Kidushin until now) into a Zenus in a direct manner. This is not the way of the Rabanan.
This seems to be Tosfos' intention.
M. Kornfeld