He thanks him for his information about the revival of Nestorianism and commends his zeal.
Leo, the bishop, to his dearly-beloved son, Eutyches, presbyter.
You have brought to our knowledge, beloved, by your letter that through the activity of some the heresy of Nestorius has been again reviving. We reply that your solicitude in this matter has pleased us, since the remarks we have received are an indication of your mind. Wherefore do not doubt that the Lord, the Founder of the Catholic Faith, will befriend you in all things. And when we have been able to ascertain more fully by whose wickedness this happens, we must make provision with the help of God for the complete uprooting of this poisonous growth which has long ago been condemned. God keep you safe, my beloved son. Dated 1st June, in the consulship of the illustrious Postumianus and Zeno (448).
Source: Letters (New Advent)