Pope Agatho Quotes
This Apostolic Church never turned from the way of truth nor held any kind of error. It is imperative that nothing of the truths which have been defined be lessened, nothing altered, nothing added, but that they be preserved intact in word and meaning. This is the true rule of faith.
We declare that no one is permitted to introduce, or to describe, or to compare, or to study, or otherwise to teach another faith. Whoever presumes to introduce or teach or pass on another creed . . . or whoever presumes to introduce a novel doctrine . . . We declare to be anathematized.