14 Animated discussions about the new Nestorian heresy were going on in the monasteries of Egypt, and the watchful Bishop writes to warn the monks of the fallacies and dangers of this doctrine, not, however, in order to foment dissensions and controversies, but (he says, so that if any should chance to attack you, you may be able to oppose their vanities with the truth, and so not only yourselves be saved from the disaster of error but also be able fraternally to convince others with suitable arguments, and thus help them to preserve forever in their hearts the pearl of that faith was delivered through the holy Apostles to the Churches.
Source: Orientalis Ecclesiae (Vatican.va)