Deuteronomy 21:15Meaning & Commentary from the Church Fathers

The cherished spouse symbolizes the synagogue, initially welcomed as the favored one into God's household. In contrast, the neglected spouse represents the daughter of the Gentiles, yet her offspring is the firstborn. Consequently, the children of the Church hold precedence in the kingdom, receiving a lesser inheritance—the teachings of the apostles and prophets. This aligns with the law which declares that the firstborn is entitled to a double share, even if he is not the child of the cherished spouse, but merely the firstborn.

This discourse draws upon the example found in the Book of Deuteronomy, which discusses a man with two wives, one favored and the other neglected. You may be concerned that this could imply he possesses two souls, but that cannot be true. You are aware that, in a symbolic sense, Scripture pertains to both the synagogue and the Church; one relates to the soul and the other to the profound truth of the Word. It also pertains to the various attributes and qualities of the soul, which may be discerned by those who engage in spiritual contemplation. Thus, in this section of the Law, it seems to me that the reference is not to two distinct souls, but rather to the different qualities of a single soul.