Creed of the Council of Chalcedon

So, following the saintly fathers, we all with one voice teach the confession of one and the same Son, our Lord Jesus Christ: the same perfect in divinity and perfect in humanity, the same truly God and truly man, of a rational soul and a body; consubstantial with the Father as regards his divinity, and the same consubstantial with us as regards his humanity; like us in all respects except for sin; begotten before the ages from the Father as regards his divinity, and in the last days the same for us and for our salvation from Mary, the virgin God-bearer as regards his humanity; one and the same Christ, Son, Lord, only-begotten, acknowledged in two natures which undergo no confusion, no change, no division, no separation; at no point was the difference between the natures taken away through the union, but rather the property of both natures is preserved and comes together into a single person and a single subsistent being; he is not parted or divided into two persons, but is one and the same only-begotten Son, God, Word, Lord Jesus Christ, just as the prophets taught from the beginning about him, and as the Lord Jesus Christ himself instructed us, and as the creed of the fathers handed it down to us.

Since we have formulated these things with all possible accuracy and attention, the sacred and universal synod decreed that no one is permitted to produce, or even to write down or compose, any other creed or to think or teach otherwise. As for those who dare either to compose another creed or even to promulgate or teach or hand down another creed for those who wish to convert to a recognition of the truth from Hellenism or from Judaism, or from any kind of heresy at all: if they be bishops or clerics, the bishops are to be deposed from the episcopacy and the clerics from the clergy; if they be monks or layfolk, they are to be anathematised.