Constantinople IV Eighth Ecumenical Council 879/880
Jointly sanctifying and preserving intact the venerable and divine teaching of our Lord and Savior Jesus Christ, which has been established in the bosom of our mind, with unhesitating resolve and purity of faith, as well as the sacred ordinances and canonical stipulations of his holy disciples and Apostles with an unwavering judgment, and indeed, those Seven holy and ecumenical Synods which were directed by the inspiration of the one and the same Holy Spirit and effected the [Christian] preaching, and jointly guarding with a most honest and unshakeable resolve the canonical institutions invulnerable and unfalsified, we expel those who removed themselves from the Church, and embrace and regard worthy of receiving those of the same faith or teachers of orthodoxy to whom honor and sacred respect is due as they themselves ordered. Thus, having in mind and declaring all these things, we embrace with mind and tongue and declare to all people with a loud voice the Horos (Rule) of the most pure faith of the Christians which has come down to us from above through the Fathers, subtracting nothing, adding nothing, falsifying nothing; for subtraction and addition, when no heresy is stirred up by the ingenious fabrications of the evil one, introduces disapprobation of those who are exempt from blame and inexcusable assault on the Fathers. As for the act of changing with falsified words the Horoi (Rules, Boundaries) of the Fathers is much worse that the previous one. Therefore, this holy and ecumenical Synod embracing whole-heartedly and declaring with divine desire and straightness of mind, and establishing and erecting on it the firm edifice of salvation, thus we think and loudly proclaim this message to all:
“I believe in One God, Father Almighty, … and in One Lord Jesus Christ, the Only-begotten Son of God… and in the Holy Spirit, the Lord … who proceeds from the Father… [the whole Creed is cited here]”
Thus we think, in this confession of faith we were we baptized, through this one the word of truth proved that every heresy is broken to pieces and canceled out. We enroll as brothers and fathers and co-heirs of the heavenly city those who think thus. If anyone, however, dares to rewrite and call Rule of Faith some other exposition besides that of the sacred Symbol which has been spread abroad from above by our blessed and holy Fathers even as far as ourselves, and to snatch the authority of the confession of those divine men and impose on it his own invented phrases and put this forth as a common lesson to the faithful or to those who return from some kind of heresy, and display the audacity to falsify completely the antiquity of this sacred and venerable Horos (Rule) with illegitimate words, or additions, or subtractions, such a person should, according to the vote of the holy and Ecumenical Synods, which has been already acclaimed before us, be subjected to complete defrocking if he happens to be one of the clergymen, or be sent away with an anathema if he happens to be one of the lay people. (Horos of the Eighth Ecumenical Council: Acts 6 & 7)
source: http://www.oodegr.com/english/dogma/synodoi/8th_Synod_Dragas.htm