I think that Aquinas is being a little too neat here. It is better to believe the creeds, and accept that there is a marked lack of comprehension of the nature of God by all humanity. Because we are not God, we may be made in his image, and we may have his word, made incarnate in Christ, but we are not God.
Nor can we attain being God. To pretend to understand what is higher than us is hubris.
12 But the nature of God is not in the Word of God thus: it is one in species and differs in number. The way in which the Word has the nature of God is the way in which God’s act of understanding is His very being, as was said. Now, the act of understanding is the divine being itself. The Word, therefore, has the divine essence itself; has it with an identity not only of species but of number.
A nature, again, which is one in species, is not divided into a numerical many except by reason of matter. But the divine nature is entirely immaterial. It is, therefore, impossible that the divine nature be specifically one and numerically different. The Word of God, therefore, has a nature in common with God and has it with numerical identity. For this reason the Word of God and the God whose Word He is are not two gods, but one God. For the fact that among us two who have human nature are two men hinges on the fact that human nature is numerically divided in those two. But we showed in Book II that things which are divided in creatures are in God simply one being; thus, in creatures the essence is one thing and the act of being another; and in some creatures even what subsists in the essence is one thing, and its essence or nature another; for this man is neither his humanity nor his act of being. But God is both His essence and His act of being.
13 And although in God these are most truly one, there is still in God whatever belongs to the notion of a subsistent, or of essence, or of being itself: for it is suitable to Him that He should not be in something, in that He is subsistent; that He be what He is, in that He is essence; and that He be in act, by reason of His act of being.
Therefore, since in God the one understanding, the act of understanding, and the intention understood are the same as His own Word, there must most truly be in God that which belongs to the notion of the one understanding, that which belongs to the notion of the act of understanding, and that which belongs to the notion of the intention understood, or word. But in the essence of interior word which is the intention understood there is this: that it proceeds from the one understanding in accord with his act of understanding, since it is, so to say, the intellectual term of the operation.
For, in the act of understanding, the intellect conceives and forms the intention or the essence understood, and this is the interior word. From God, therefore, in His very act of understanding must His Word proceed. The Word of God is, therefore, compared to God understanding (whose Word He is) as to Him from whom He is, for this is essential to a word. Therefore, although in God the one understanding, the act of understanding and the intention understood, or Word, are by essence one, and although for this reason each is necessarily God, there remains the distinction of relation alone, in so far as the Word is related to the one who conceives as to Him from whom He is.
This is why the Evangelist, seeing that he had said: “God was the Word,” to keep one from understanding that all distinction between the Word and God speaking or conceiving the Word was taken away, added this: “This was in the beginning with God”; as though to say: “This Word, whom I have called God, is in a way distinct from God speaking, and so it can be said that He was with God.”
14 Of course, the word interiorly conceived is a kind of account and likeness of the thing understood. Now, a likeness of one thing existing in another is essentially an exemplar if it stands to the other as principle, or it is essentially an image if it is related to that whose likeness it is as to a principle. Now, in our intellect one sees an example of each of these situations.
For, since the likeness of the artefact existing in the mind of the artist is the principle of the operation which constitutes the artefact, the likeness is related to the artefact as an exemplar to that exemplified; but the likeness of a natural thing conceived in our intellect is related to the thing whose likeness it is as to its beginning, for our act of understanding takes its beginning from the senses which are changed by natural things.
Since, of course, God understands both Himself and other things, as was shown in Book I, His act of understanding is the principle of things understood by Him, since they are caused by His intellect and will; but His act of understanding is referred to the intelligible which He Himself is as to a beginning, for this intelligible is identified with the intellect understanding, whose emanation, so to say, is the Word conceived. Therefore, the Word of God must be referred to the other things understood by God as exemplar, and must be referred to God Himself whose Word He is as image. Hence, one reads of the Word of God in Colossians (1:15) that He is “the image of the invisible God.”
15 Now, there is a difference between intellect and sense, for sense grasps a thing in its exterior accidents, which are color, taste, quantity and others of this kind, but intellect enters into what is interior to the thing. And, since every knowledge is perfected by the likeness between the knower and the known, there must be in the sense a likeness of the thing in its sensible accidents, but in the intellect there must be a likeness of the thing understood in its essence.
Therefore, the word conceived in the intellect is the image or the exemplar of the substance of the thing understood. Since, then, the Word of God is the image of God (as we have shown), it is necessarily the image of God in His essence. Hence, we have what the Apostle says, that He is “the figure of the substance of God” (Heb. 1:3).
Calvin notes that we have fallen from the state we were created in, and that the sin of Adam was wilful disobediance, associated with belieivng lies about God, and believing we could be like God. Which brings me back to the first point. We are not God, and we cannot understand God apart from what he reveals to us.
While revealed truth concurs with the general consent of mankind in teaching that the second part of wisdom consists in self-knowledge, they differ greatly as to the method by which this knowledge is to be acquired. In the judgment of the flesh man deems his self-knowledge complete, when, with overweening confidence in his own intelligence and integrity, he takes courage, and spurs himself on to virtuous deeds, and when, declaring war upon vice, he uses his utmost endeavour to attain to the honourable and the fair. But he who tries himself by the standard of divine justice, finds nothing to inspire him with confidence; and hence, the more thorough his self-examination, the greater his despondency. Abandoning all dependence on himself, he feels that he is utterly incapable of duly regulating his conduct. It is not the will of God, however, that we should forget the primeval dignity which he bestowed on our first parents—a dignity which may well stimulate us to the pursuit of goodness and justice. It is impossible for us to think of our first original, or the end for which we were created, without being urged to meditate on immortality, and to seek the kingdom of God. But such meditation, so far from raising our spirits, rather casts them down, and makes us humble. For what is our original? One from which we have fallen. What the end of our creation? One from which we have altogether strayed, so that, weary of our miserable lot, we groan, and groaning sigh for a dignity now lost. When we say that man should see nothing in himself which can raise his spirits, our meaning is, that he possesses nothing on which he can proudly plume himself. Hence, in considering the knowledge which man ought to have of himself, it seems proper to divide it thus, first, to consider the end for which he was created, and the qualities—by no means contemptible qualities—with which he was endued, thus urging him to meditate on divine worship and the future life; and, secondly, to consider his faculties, or rather want of faculties—a want which, when perceived, will annihilate all his confidence, and cover him with confusion. The tendency of the former view is to teach him what his duty is, of the latter, to make him aware how far he is able to perform it. We shall treat of both in their proper order.
As the act which God punished so severely must have been not a trivial fault, but a heinous crime, it will be necessary to attend to the peculiar nature of the sin which produced Adam’s fall, and provoked God to inflict such fearful vengeance on the whole human race. The common idea of sensual intemperance is childish. The sum and substance of all virtues could not consist in abstinence from a single fruit amid a general abundance of every delicacy that could be desired, the earth, with happy fertility, yielding not only abundance, but also endless variety. We must, therefore, look deeper than sensual intemperance. The prohibition to touch the tree of the knowledge of good and evil was a trial of obedience, that Adam, by observing it, might prove his willing submission to the command of God. For the very term shows the end of the precept to have been to keep him contented with his lot, and not allow him arrogantly to aspire beyond it. The promise, which gave him hope of eternal life as long as he should eat of the tree of life, and, on the other hand, the fearful denunciation of death the moment he should taste of the tree of the knowledge of good and evil, were meant to prove and exercise his faith. Hence it is not difficult to infer in what way Adam provoked the wrath of God. Augustine, indeed, is not far from the mark, when he says (in Psal. 19), that pride was the beginning of all evil, because, had not man’s ambition carried him higher than he was permitted, he might have continued in his first estate. A further definition, however, must be derived from the kind of temptation which Moses describes. When, by the subtlety of the devil, the woman faithlessly abandoned the command of God, her fall obviously had its origin in disobedience. This Paul confirms, when he says, that, by the disobedience of one man, all were destroyed. At the same time, it is to be observed, that the first man revolted against the authority of God, not only in allowing himself to be ensnared by the wiles of the devil, but also by despising the truth, and turning aside to lies. Assuredly, when the word of God is despised, all reverence for Him is gone. His majesty cannot be duly honoured among us, nor his worship maintained in its integrity, unless we hang as it were upon his lips. Hence infidelity was at the root of the revolt. From infidelity, again, sprang ambition and pride, together with ingratitude; because Adam, by longing for more than was allotted him, manifested contempt for the great liberality with which God had enriched him. It was surely monstrous impiety that a son of earth should deem it little to have been made in the likeness, unless he were also made the equal of God. If the apostasy by which man withdraws from the authority of his Maker, nay, petulantly shakes off his allegiance to him, is a foul and execrable crime, it is in vain to extenuate the sin of Adam. Nor was it simple apostasy. It was accompanied with foul insult to God, the guilty pair assenting to Satan’s calumnies when he charged God with malice, envy, and falsehood. In fine, infidelity opened the door to ambition, and ambition was the parent of rebellion, man casting off the fear of God, and giving free vent to his lust. Hence, Bernard truly says, that, in the present day, a door of salvation is opened to us when we receive the gospel with our ears, just as by the same entrance, when thrown open to Satan, death was admitted. Never would Adam have dared to show any repugnance to the command of God if he had not been incredulous as to his word. The strongest curb to keep all his affections under due restraint, would have been the belief that nothing was better than to cultivate righteousness by obeying the commands of God, and that the highest possible felicity was to be loved by him. Man, therefore, when carried away by the blasphemies of Satan, did his very utmost to annihilate the whole glory of God.
We live in a fallen time, as part of a fallen race. We should be profoundly grateful that the word became flesh, incarnate in Christ: truly God, truly man. This should hurt our heads: we are truly fallen, sinful men, and there is no part of us that is truly God, unless the spirit of God is with us.