10 How do we find this in these three names, “I am the God of Abraham, and the God of Isaac, and the God of Jacob”? We hold the bond women among the evil, and the free women among the good. Free women bear the good; Sarah bare Isaac: bond women bear the evil; Hagar bare Ishmael. We have in the case of Abraham alone the two sorts, both when the good are of the good, and also when the evil are of the evil. But where have we evil of good figured? Rebecca, Isaac's wife, was a free woman: read, She bare twins; one was good, the other evil.
You have the Scripture openly declaring by the voice of God, “Jacob have I loved, but Esau have I hated.” Rebecca bare those two, Jacob and Esau: one of them is chosen, the other is reprobated; one succeeds to the inheritance, the other is disinherited. God does not make His people of Esau, but makes it of Jacob. The seed is one, those conceived are dissimilar: the womb is one, those born of it are diverse. Was not the free woman that bare Jacob, the same free woman that bare Esau?
They strove in the mother's womb; and when they strove there, it was said to Rebecca, “Two peoples are in your womb.” Two men, two peoples; a good people, and a bad people: but yet they strive in one womb. How many evil men there are in the Church! And one womb carries them until they are separated in the end: and the good cry out against the evil, and the evil in turn cry out against the good, and both strive together in the bowels of one mother. Will they be always together? There is a going forth to the light in the end; the birth which is here figured in a mystery is declared; and it will then appear that “Jacob have I loved, but Esau have I hated.”
Source: Tractates on the Gospel of John (New Advent)