אלה תולדות יצחק בן אברהם, אברהם הולד את יצחק
The opening pasuk of the parsha seems redundant. If Yitzchak was Avraham’s son, then obviously Avraham was his biological father. Rashi explains that the redundancy is deliberate, to attest that Yitzchak was unmistakably Avraham Avinu’s son both biologically and spiritually. Apparently, the leitzanim, cynics, were spreading the lie that Sarah had conceived through relations with Avimelech when she was in Gerar. They claimed that, at his advanced age, Avraham could no longer have children. [They ignored Yishmael’s birth.] In order to set the record straight, Hashem formed Yitzchak’s countenance to be exactly the same as that of Avraham. No question…
