3 Let us therefore consider what we are taught here; since both those deeds were typical of us, and these words exhort us to recognise ourselves. For if we hold with a firm heart the grace of God which has been given us, we are Israel, the seed of Abraham: unto us the Apostle says, “Therefore are you the seed of Abraham.”...Let therefore no Christian consider himself alien to the name of Israel. For we are joined in the corner stone with those among the Jews who believed, among whom we find the Apostles chief. Hence our Lord in another passage says, “And other sheep I have, which are not of this fold; them also I must bring, that there may be one fold and one Shepherd.” The Christian people then is rather Israel, and the same is preferably the house of Jacob; for Israel and Jacob are the same. But that multitude of Jews, which was deservedly reprobated for its perfidy, for the pleasures of the flesh sold their birthright, so that they belonged not to Jacob, but rather to Esau. For you know that it was said with this hidden meaning, “That the elder shall serve the younger.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)