Leo the Great

Just as the well-being of the churches causes us gratification, so we are deeply saddened whenever we learn of any liberties taken with, or acts committed against, canon law and ecclesiastical discipline. We cannot excuse ourselves to him who wished us to be on the watch if we do not repress such practices with the vigilance we should. We cannot excuse ourselves if we permit the unsullied body of the church (which we are bound to keep clean from all dirt) to be defiled by contact with those who pursue evil ends. For the very union of the members gets inharmonious elements in it through carelessness.

As a result, dearly beloved, it was necessary (by the designs of a secret plan) for the unchangeable God (whose will cannot be separated from his goodness) to complete by a deeper mystery the first intentions of his love. It was necessary that human beings, tricked into sin by the devil’s wickedness, should not perish in opposition to God’s plan.