Canon 7 No faith may be composed other than Nicaea's

When these things had been read, the holy synod decreed that it is lawful for no one to bring forward, that is, to write or compose, a faith other than that defined by the holy Fathers who were gathered in the city of the Nicaeans, with the Holy Spirit. And those who dare either to compose another faith, or to present it, or to offer it to those who wish to turn to the knowledge of the truth, whether from paganism, or from Judaism, or from any heresy whatsoever: these, if they are bishops or clerics, are to be alien, the bishops from the episcopate and the clerics from the clergy; and if they are laymen, they are to be anathematised. And in the same manner, if any are detected, whether bishops, or clerics, or laymen, either holding or teaching the things in the exposition presented by Charisius the presbyter concerning how the only-begotten Son of God became man, that is, the foul and perverted doctrines of Nestorius, which are also subjoined, let them be subject to the sentence of this holy and ecumenical council; so that, that is to say, the bishop is to be alienated from the episcopate and to be deposed, and the cleric likewise is to fall from the clergy; and if anyone is a layman, let him too be anathematised, as has been said before.