II. They are to be told that the Catholic Faith rejects both the Eutychian and the Nestorian extremes. He wishes to be informed how far she succeeds.
If then the aforesaid revere and love the name of “Catholic,” and wish to be numbered among the members of the Lord's body, let them reject the crooked errors which in their rashness they have committed, and let them show penitence for their wicked blasphemies and deeds of bloodshed. For the salvation of their souls let them yield to the synodal decrees which have been confirmed in the city of Chalcedon. And because nothing but true faith and quiet humility attains to the understanding of the mystery of man's salvation, let them believe what they read in the Gospel, what they confess in the Creed, and not mix themselves up with unsound doctrines. For as the Catholic Faith condemns Nestorius, who dared to maintain two persons in our one Lord Jesus Christ, so does it also condemn Eutyches and Dioscorus who deny that the true human flesh was assumed in the Virgin Mother's womb by the only-begotten Word of God.
If your exhortations have any success in convincing these persons, which will win for you eternal glory, I beseech your clemency to inform me of it by letter; that I may have the joy of knowing that you have reaped the fruit of your good work, and that they through the Lord's mercy have not perished. Dated the 15th of June, in the consulship of the illustrious Opilio (453).
Source: Letters (New Advent)