4 On this faith being publicly put forth by us, no room for contradiction appeared; but our most pious Emperor, before any one else, testified that it comprised most orthodox statements. He confessed moreover that such were his own sentiments, and he advised all present to agree to it, and to subscribe its articles and to assent to them, with the insertion of the single word, One-in-essence, which moreover he interpreted as not in the sense of the affections of bodies, nor as if the Son subsisted from the Father in the way of division, or any severance; for that the immaterial, and intellectual, and incorporeal nature could not be the subject of any corporeal affection, but that it became us to conceive of such things in a divine and ineffable manner. And such were the theological remarks of our most wise and most religious Emperor; but they, with a view to the addition of One in essence, drew up the following formula:—
The Faith dictated in the Council.
“We believe in One God, the Father Almighty, Maker of all things visible and invisible:”—
“And in One Lord Jesus Christ, the Son of God, begotten of the Father, Only-begotten, that is, from the essence of the Father; God from God, Light from Light, Very God from Very God, begotten not made, One in essence with the Father, by Whom all things were made, both things in heaven and things in earth; Who for us men and for our salvation came down and was made flesh, was made man, suffered, and rose again the third day, ascended into heaven, and comes to judge quick and dead.”
“And in the Holy Ghost.”
“And those who say, 'Once He was not,' and 'Before His generation He was not,' and 'He came to be from nothing,' or those who pretend that the Son of God is 'Of other subsistence or essence,' or 'created' or 'alterable,' or 'mutable,' the Catholic Church anathematizes.”
Source: Letter on the Council of Nicaea (New Advent)