For Scripture says, “Jacob loved him (Joseph) because he was the son of his old age” (Gen 37:3). Thus in a world that had become old and was entirely lost, the Son of God, who had been manifested and born of the Virgin, appeared to the eyes of the Father “the son of old age.” Even before all ages, from everlasting, he is with God.
“By the blessing of the breasts and of the womb of your father and your mother” (Gen 49:25-26, Septuagint). Blessing of breasts: or rather, of the two Testaments, from which came forth the preaching that announced the future appearance of the Word in the world; breasts with which he nurses and feeds us, presenting us to God as sons. Or he designates with these words the breasts of Mary, from which he took suck, breasts that were blessed and of which a woman, crying out, said, “Blessed is the womb that bore you and the breasts that you sucked!” (Lk 11:27).
By saying in addition, “And of the blessing of the womb of your father and your mother,” the prophet is foretelling a spiritual mystery. For he could have said, “And of the blessing of the womb of your mother,” to indicate, with this expression, Mary, in whose womb the Word was carried for nine months. Yet he did not say this; instead he says, “and from the blessing of the womb of your father and your mother.” Joining the two ideas in this way, he made them a single reality, so that it would be clearly understood that both that which exists according to the spirit and that which is according to the flesh belong to this one Person. For the Word proceeded from one heart of the Father and from the holy womb (of Mary), being born from one womb of the Father, as he says through the mouth of the prophet, “My heart speaks a good Word” (Ps 45:1).
On the other hand, in the last days, he came forth, according to the flesh, from a virginal womb after having been carried for nine months, so that, after having been born a second time from the womb of his Mother, he might manifest himself visibly. Therefore he says, also through the prophet, “Thus says the Lord who formed me from (my Mother’s) womb to be his servant” (Is 49:5).
—On the Blessings of the Patriarchs 1: PO 27, 108-12, as found in Luigi Gambero’s Mary and the Fathers of the Church: The Blessed Virgin Mary in Patristic Thought, Ignatius, 1999.