1 Cor. 1:10: "That you all speak the same thing, and that there be no
schisms among you": and this could not be secured unless any question
of faith that may arise be decided by him who presides over the whole
Church, so that the whole Church may hold firmly to his decision.
Consequently it belongs to the sole authority of the Sovereign
Pontiff to publish a new edition of the symbol, as do all other
matters which concern the whole Church, such as to convoke a general
council and so forth.

Reply Obj. 1: The truth of faith is sufficiently explicit in the
teaching of Christ and the apostles. But since, according to 2 Pet.
3:16, some men are so evil-minded as to pervert the apostolic
teaching and other doctrines and Scriptures to their own destruction,
it was necessary as time went on to express the faith more explicitly
against the errors which arose.

Reply Obj. 2: This prohibition and sentence of the council was
intended for private individuals, who have no business to decide
matters of faith: for this decision of the general council did not
take away from a subsequent council the power of drawing up a new
edition of the symbol, containing not indeed a new faith, but the
same faith with greater explicitness. For every council has taken
into account that a subsequent council would expound matters more
fully than the preceding council, if this became necessary through
some heresy arising. Consequently this belongs to the Sovereign
Pontiff, by whose authority the council is convoked, and its
decision confirmed.

Reply Obj. 3: Athanasius drew up a declaration of faith, not under
the form of a symbol, but rather by way of an exposition of doctrine,