XI. And besides all this, there is the absolutely impossible and inadmissible, as that which we are now examining. For as we assert that it is impossible for God to be evil, or not to exist-for this would be indicative of weakness in God rather than of strength-or for the non-existent to exist, or for two and two to make both four and ten, so it is impossible and inconceivable that the Son should do anything that the Father does not. For all things that the Father has are the Son's; and on the other hand, all that belongs to the Son is the Father's. Nothing then is peculiar, because all things are in common. For Their Being itself is common and equal, even though the Son receive it from the Father. It is in respect of this that it is said I live by the Father; not as though His Life and Being were kept together by the Father, but because He has His Being from Him beyond all time, and beyond all cause. But how does He see the Father doing, and do likewise? Is it like those who copy pictures and letters, because they cannot attain the truth unless by looking at the original, and being led by the hand by it? But how shall Wisdom stand in need of a teacher, or be incapable of acting unless taught? And in what sense does the Father "Do" in the present or in the past? Did He make another world before this one, or is He going to make a world to come? And did the Son look at that and make this? Or will He look at the other, and make one like it? According to this argument there must be Four worlds, two made by the Father, and two by the Son. What an absurdity! He cleanses lepers, and delivers men from evil spirits, and diseases, and quickens the dead, and walks upon the sea, and does all His other works; but in what case, or when did the Father do these acts before Him? Is it not clear that the Father impressed the ideas of these same actions, and the Word brings them to pass, yet not in slavish or unskilful fashion, but with full knowledge and in a masterly way, or, to speak more properly, like the Father? For in this sense I understand the words that whatsoever is done by the Father, these things does the Son likewise; not, that is, because of the likeness of the things done, but in respect of the Authority. This might well also be the meaning of the passage which says that the Father works hitherto and the Son also; and not only so but it refers also to the government and preservation of the things which He has made; as is shown by the passage which says that He makes His Angels Spirits, and that the earth is founded upon its steadfastness (though once for all these things were fixed and made) and that the thunder is made firm and the wind created. Of all these things the Word was given once, but the Action is continuous even now.
XII. Let them quote in the seventh place that The Son came down from Heaven, not to do His own Will, but the Will of Him That sent Him. Well, if this had not been said by Himself Who came down, we should say that the phrase was modelled as issuing from the Human Nature, not from Him who is conceived of in His character as the Saviour, for His Human Will cannot be opposed to God, seeing it is altogether taken into God; but conceived of simply as in our nature, inasmuch as the human will does not completely follow the Divine, but for the most part struggles against and resists it. For we understand in the same way the words, Father, if it be possible, let this cup pass from Me; Nevertheless let not what I will but Your Will prevail. For it is not likely that He did not know whether it was possible or not, or that He would oppose will to will. But since, as this is the language of Him Who assumed our Nature (for He it was Who came down), and not of the Nature which He assumed, we must meet the objection in this way, that the passage does not mean that the Son has a special will of His own, besides that of the Father, but that He has not; so that the meaning would be, "not to do Mine own Will, for there is none of Mine apart from, but that which is common to, Me and You; for as We have one Godhead, so We have one Will." For many such expressions are used in relation to this Community, and are expressed not positively but negatively; as, e.g., God gives not the Spirit by measure, for as a matter of fact He does not give the Spirit to the Son, nor does He measure It, for God is not measured by God; or again, Not my transgression nor my sin. The words are not used because He has these things, but because He has them not. And again, Not for our righteousness which we have done, for we have not done any. And this meaning is evident also in the clauses which follow. For what, says He, is the Will of My Father? That everyone that believes on the Son should be saved, and obtain the final Resurrection. Now is this the Will of the Father, but not of the Son? Or does He preach the Gospel, and receive men's faith against His will? Who could believe that? Moreover, that passage, too, which says that the Word which is heard is not the Son's but the Father's has the same force. For I cannot see how that which is common to two can be said to belong to one alone, however much I consider it, and I do not think any one else can. If then you hold this opinion concerning the Will, you will be right and reverent in your opinion, as I think, and as every right-minded person thinks.
Source: Orations (New Advent)