Defence of the Council's Phrases, from the essence, And one in essence. Objection that the phrases are not scriptural; we ought to look at the sense more than the wording; evasion of the Ariansas to the phrase of God which is in Scripture; their evasion of all explanations but those which the Council selected, which were intended to negative the Arianformulæ; protest against their conveying any material sense
20 Again, when the Bishops said that the Word must be described as the True Power and Image of the Father, in all things exact and like the Father, and as unalterable, and as always, and as in Him without division (for never was the Word not, but He was always, existing everlastingly with the Father, as the radiance of light), Eusebius and his fellows endured indeed, as not daring to contradict, being put to shame by the arguments which were urged against them; but withal they were caught whispering to each other and winking with their eyes, that 'like,' and 'always,' and 'power,' and 'in Him,' were, as before, common to us and the Son, and that it was no difficulty to agree to these. As to 'like,' they said that it is written of us, 'Man is the image and glory of God:' 'always,' that it was written, 'For we which live are always:' 'in Him,' 'In Him we live and move and have our being:' 'unalterable,' that it is written, 'Nothing shall separate us from the love of Christ:' as to 'power,' that the caterpillar and the locust are called 'power' and 'great power,' and that it is often said of the people, for instance, 'All the power of the Lord came out of the land of Egypt:' and there are others also, heavenly ones, for Scripture says, 'The Lord of powers is with us, the God of Jacob is our refuge. ' Indeed Asterius, by title the sophist, had said the like in writing, having learned it from them, and before him Arius having learned it also, as has been said. But the Bishops discerning in this too their dissimulation, and whereas it is written, 'Deceit is in the heart of the irreligious that imagine evil,' were again compelled on their part to collect the sense of the Scriptures, and to re-say and re-write what they had said before, more distinctly still, namely, that the Son is 'one in essence ' with the Father: by way of signifying, that the Son was from the Father, and not merely like, but the same in likeness, and of showing that the Son's likeness and unalterableness was different from such copy of the same as is ascribed to us, which we acquire from virtue on the ground of observance of the commandments. For bodies which are like each other may be separated and become at distances from each other, as are human sons relatively to their parents (as it is written concerning Adam and Seth, who was begotten of him that he was like him after his own pattern); but since the generation of the Son from the Father is not according to the nature of men, and not only like, but also inseparable from the essence of the Father, and He and the Father are one, as He has said Himself, and the Word is ever in the Father and the Father in the Word, as the radiance stands towards the light (for this the phrase itself indicates), therefore the Council, as understanding this, suitably wrote 'one in essence,' that they might both defeat the perverseness of the heretics, and show that the Word was other than originated things. For, after thus writing, they at once added, 'But they who say that the Son of God is from nothing, or created, or alterable, or a work, or from other essence, these the Holy Catholic Church anathematizes. ' And by saying this, they showed clearly that 'of the essence,' and 'one in essence,' are destructive of those catchwords of irreligion, such as 'created,' and 'work,' and 'originated,' and 'alterable,' and 'He was not before His generation.' And he who holds these, contradicts the Council; but he who does not hold with Arius, must needs hold and intend the decisions of the Council, suitably regarding them to signify the relation of the radiance to the light, and from thence gaining the illustration of the truth.
21. Therefore if they, as the others, make an excuse that the terms are strange, let them consider the sense in which the Council so wrote, and anathematize what the Council anathematized; and then if they can, let them find fault with the expressions. But I well know that, if they hold the sense of the Council, they will fully accept the terms in which it is conveyed; whereas if it be the sense which they wish to complain of, all must see that it is idle in them to discuss the wording, when they are but seeking handles for irreligion. This then was the reason of these expressions; but if they still complain that such are not scriptural, that very complaint is a reason why they should be cast out, as talking idly and disordered in mind. And let them blame themselves in this matter, for they set the example, beginning their war against God with words not in Scripture. However, if a person is interested in the question, let him know, that, even if the expressions are not in so many words in the Scriptures, yet, as was said before, they contain the sense of the Scriptures, and expressing it, they convey it to those who have their hearing unimpaired for religious doctrine. Now this circumstance it is for you to consider, and for those ill-instructed men to give ear to. It has been shown above, and must be believed as true, that the Word is from the Father, and the only Offspring proper to Him and natural. For whence may one conceive the Son to be, who is the Wisdom and the Word, in whom all things came to be, but from God Himself? However, the Scriptures also teach us this, since the Father says by David, 'My heart uttered a good Word,' and, 'From the womb before the morning star I begot You;' and the Son signifies to the Jews about Himself, 'If God were your Father, you would love Me; for I proceeded forth from the Father.' And again; 'Not that anyone has seen the Father, save He which is from God, He has seen the Father. ' And moreover, 'I and My Father are one,' and, 'I in the Father and the Father in Me,' is equivalent to saying, 'I am from the Father, and inseparable from Him.' And John in saying, 'The Only-begotten Son which is in the bosom of the Father, He has declared Him, ' spoke of what He had learned from the Saviour. Besides, what else does 'in the bosom' intimate, but the Son's genuine generation from the Father?
Source: De Decretis (New Advent)