If any one affirms that the Son of God who is before the ages is one, and He who has appeared in these last times is another, and refuses to acknowledge that He who is before the ages is the same with Him who appeared in these last times, even as it is written, let him be anathema.
Explication.
How could it be said that the Son of God who is before the ages, and He who has appeared in these last times, are different, when the Lord Himself says, “Before Abraham was, I am;” and, “I came forth from God, and I come, and again I go to my Father?”
Reproduced in full. Translation: Ante-Nicene Fathers, vol. 6 (Roberts and Donaldson, 1886), public domain (Public domain).