Hilary Con Const., 27

We have reviewed, beloved brethren, all the definitions of faith made by the Eastern bishops which they formulated in their assembly against the recently emerging heresy. And we, as far as we have been able, have adapted the wording of our exposition to express their meaning, following their diction rather than desiring to be thought the originators of new phrases. In these words they decree the principles of their conscience and a long maintained doctrine against a new and profane impiety. Those who compiled this heresy at Sirmium, or accepted it after its compilation, they have thereby compelled to confess their ignorance and to sign such decrees. There the Son is the perfect image of the Father: there under the qualities of an identical essence, the Person of the Son is not annihilated and confounded with the Father: there the Son is declared to be image of the Father in virtue of a real likeness, and does not differ in substance from the Father, whose image He is: there on account of the life which the Father has and the life which the Son has received, the Father can have nothing different in substance (this being implied in life) from that which the Son received to have: there the begotten Son is not a creature, but is a Person undistinguished from the Father’s nature: there, just as an identical might belongs to the Father and the Son, so their essence admits of no difference: there the Father by begetting the Son in no wise degenerates from Himself in Him through any difference of nature: there, though the likeness of nature is the same in each, the proper qualities which mark this likeness are repugnant to a confusion of Persons, so that there is not one subsisting Person who is called both Father and Son: there, though it is piously affirmed that there is both a Father who sends and a Son who is sent, yet no distinction in essence is drawn between the Father and the Son, the Sent and the Sender: there the truth of God’s Fatherhood is not bound by limits of times: there the Son is not later in time: there beyond all time is a perfect birth which refutes the error that the Son could not be born.