ויעתר יצחק לד' לנכח אשתו כי עקרה היא ויעתר לו ד'
Rashi explains that Hashem listened to Yitzchak’s plea over that of Rivkah, because there is no comparison between the effect of the prayer offered by a tzaddik ben tzaddik, righteous person who is the son of a righteous person, to that of a tzaddik ben rasha, righteous person whose father was evil. Rashi’s explanation is well-known, and it sets the standard for tefillah: A person’s righteous lineage makes a difference. This obviously presents a question to the rational mind: Is the efficacy of the prayers of someone whose roots are murky intrinsically limited? One would assume that the tefillos of…