This pasuk seems to be the source for the concept that marriages are made in Heaven. Indeed, this idea is reaffirmed in Navi and Kesuvim. In the Midrash, Chazal question, “From where did this decision come?” The Midrash offers two replies. Some say that the decision emanated from Har Ha’moriah, the scene of the akeidas Yitzchak. It was at this place that Yitzchak demonstrated the exceptional devotion to Hashem which merited him the Divine blessing.
Others reply that the pasuk is referring to the statement in pasuk 51, “Let her be the wife of your master’s son.” Here the pasuk seems to focus upon Yitzchak as Avraham’s son. How are we to understand these two disparate responses of the Midrash?
Horav Eli Munk z.l., interprets the two explanations in the Midrash to reflect varied perspectives concerning one’s potential focus in choosing a mate. For some, the prime factor in the choice of a mate is his/her personal merit or “yichus atzmi.” Others view the ethical integrity of the family, the “zchus avos,” merit of the ancestors, the “yichus mispachti,” as the best assurance of virtuous progeny. We must add that by no means does one preclude the other. It is only a question as to which of these two factors is more likely to catalyze the “Divine blessing.”