Excerpted from Rebbetzin Tziporah Heller’s Question and Answer series on Naaleh.com
Why wasn’t the spiritual goal of building Klal Yisrael adequate to bond Leah to Yaakov in the same way it bonded him to Rachel?
By definition special love is unique and exclusive and cannot be directed towards two people. Therefore, Yaakov’s love for Leah could not be like the love he had for Rachel. Had the world been on a higher level, Yaakov would have had one wife. Rachel would have had within her both her own attributes and the spiritual attributes of Leah. Yaakov would have had within him both the spiritual forces of Yaakov and Yisrael.
Rachel was the more practical of the two sisters, the one who could address the revealed physical world. Since we are meant to bring the idealism of Leah into the world of Rachel, Rachel became the akeret habayit, the mainstay of the house of Israel.