Rav
Yehudah was not sure how to find a genealogically fit wife for his son.
Ulla said to him, - do we know from where we ourselves come? We might
be descended from those "...who lie upon beds of ivory and defile their couches.” Rather, go after silence, that is, find family whose members are quiet and peaceable.
If
you see two families in conflict with one another, you can assume that
there is some genealogical flaw in one of them, and because of that
flaw Heaven will not allow one of them to cleave to the other.
